diff --git a/examples/multithread/multithread.cc b/examples/multithread/multithread.cc
index 4233bc71..b679e406 100644
--- a/examples/multithread/multithread.cc
+++ b/examples/multithread/multithread.cc
@@ -40,7 +40,7 @@ int main (int argc, char *argv[]) {
     modsec->setConnectorInformation("ModSecurity-test v0.0.1-alpha (Simple " \
         "example on how to use ModSecurity API");
 
-    char main_rule_uri[] = "basic_rules.conf";
+    const char main_rule_uri[] = "basic_rules.conf";
     auto rules = std::make_unique<modsecurity::RulesSet>();
     if (rules->loadFromUri(main_rule_uri) < 0) {
         std::cerr << "Problems loading the rules..." << std::endl;
diff --git a/headers/modsecurity/anchored_set_variable_translation_proxy.h b/headers/modsecurity/anchored_set_variable_translation_proxy.h
index 10f3f7f2..37767b98 100644
--- a/headers/modsecurity/anchored_set_variable_translation_proxy.h
+++ b/headers/modsecurity/anchored_set_variable_translation_proxy.h
@@ -42,7 +42,7 @@ class AnchoredSetVariableTranslationProxy {
         : m_name(name),
         m_fount(fount)
     {
-        m_translate = [](std::string *name, std::vector<const VariableValue *> *l) {
+        m_translate = [](const std::string *name, std::vector<const VariableValue *> *l) {
             for (int i = 0; i < l->size(); ++i) {
                 VariableValue *newVariableValue = new VariableValue(name, &l->at(i)->getKey(), &l->at(i)->getKey());
                 const VariableValue *oldVariableValue = l->at(i);
diff --git a/headers/modsecurity/rule_with_actions.h b/headers/modsecurity/rule_with_actions.h
index aee16d8c..541eb3f4 100644
--- a/headers/modsecurity/rule_with_actions.h
+++ b/headers/modsecurity/rule_with_actions.h
@@ -79,7 +79,7 @@ class RuleWithActions : public Rule {
         bool chainedParentNull = false) const;
 
     std::vector<actions::Action *> getActionsByName(const std::string& name,
-        Transaction *t);
+        const Transaction *t);
     bool containsTag(const std::string& name, Transaction *t);
     bool containsMsg(const std::string& name, Transaction *t);
 
diff --git a/headers/modsecurity/rule_with_operator.h b/headers/modsecurity/rule_with_operator.h
index d0297409..7fb9b2d2 100644
--- a/headers/modsecurity/rule_with_operator.h
+++ b/headers/modsecurity/rule_with_operator.h
@@ -62,7 +62,7 @@ class RuleWithOperator : public RuleWithActions {
     static void cleanMatchedVars(Transaction *trasn);
 
 
-    std::string getOperatorName() const;
+    const std::string& getOperatorName() const;
 
     virtual std::string getReference() override {
         return std::to_string(m_ruleId);
diff --git a/headers/modsecurity/rules.h b/headers/modsecurity/rules.h
index a9bfb80d..cb83dedb 100644
--- a/headers/modsecurity/rules.h
+++ b/headers/modsecurity/rules.h
@@ -50,7 +50,7 @@ class Rules {
     int append(Rules *from, const std::vector<int64_t> &ids, std::ostringstream *err) {
          size_t j = 0;
          for (; j < from->size(); j++) {
-            RuleWithOperator *rule = dynamic_cast<RuleWithOperator *>(from->at(j).get());
+            const RuleWithOperator *rule = dynamic_cast<RuleWithOperator *>(from->at(j).get());
             if (rule && std::binary_search(ids.begin(), ids.end(), rule->m_ruleId)) {
                  if (err != NULL) {
                      *err << "Rule id: " << std::to_string(rule->m_ruleId) \
@@ -68,7 +68,7 @@ class Rules {
     }
 
     bool insert(std::shared_ptr<Rule> rule, const std::vector<int64_t> *ids, std::ostringstream *err) {
-        RuleWithOperator *r = dynamic_cast<RuleWithOperator *>(rule.get());
+        const RuleWithOperator *r = dynamic_cast<RuleWithOperator *>(rule.get());
         if (r && ids != nullptr && std::binary_search(ids->begin(), ids->end(), r->m_ruleId)) {
             if (err != nullptr) {
                 *err << "Rule id: " << std::to_string(r->m_ruleId) \
diff --git a/headers/modsecurity/rules_set.h b/headers/modsecurity/rules_set.h
index c5616cc4..e1574594 100644
--- a/headers/modsecurity/rules_set.h
+++ b/headers/modsecurity/rules_set.h
@@ -93,7 +93,7 @@ extern "C" {
 #endif
 
 RulesSet *msc_create_rules_set(void);
-void msc_rules_dump(RulesSet *rules);
+void msc_rules_dump(const RulesSet *rules);
 int msc_rules_merge(RulesSet *rules_dst, RulesSet *rules_from, const char **error);
 int msc_rules_add_remote(RulesSet *rules, const char *key, const char *uri,
     const char **error);
diff --git a/headers/modsecurity/rules_set_properties.h b/headers/modsecurity/rules_set_properties.h
index 643abce8..386a252d 100644
--- a/headers/modsecurity/rules_set_properties.h
+++ b/headers/modsecurity/rules_set_properties.h
@@ -70,7 +70,7 @@ class ConfigInt {
     bool m_set;
     int m_value;
 
-    void merge(ConfigInt *from) {
+    void merge(const ConfigInt *from) {
         if (m_set == true || from->m_set == false) {
             return;
         }
@@ -87,7 +87,7 @@ class ConfigDouble {
     bool m_set;
     double m_value;
 
-    void merge(ConfigDouble *from) {
+    void merge(const ConfigDouble *from) {
         if (m_set == true || from->m_set == false) {
             return;
         }
@@ -104,7 +104,7 @@ class ConfigString {
     bool m_set;
     std::string m_value;
 
-    void merge(ConfigString *from) {
+    void merge(const ConfigString *from) {
         if (m_set == true || from->m_set == false) {
             return;
         }
@@ -150,7 +150,7 @@ class ConfigUnicodeMap {
     static void loadConfig(std::string f, double codePage,
         RulesSetProperties *driver, std::string *errg);
 
-    void merge(ConfigUnicodeMap *from) {
+    void merge(const ConfigUnicodeMap *from) {
         if (from->m_set == false) {
             return;
         }
diff --git a/headers/modsecurity/transaction.h b/headers/modsecurity/transaction.h
index 488e6c5a..0b7bd7e4 100644
--- a/headers/modsecurity/transaction.h
+++ b/headers/modsecurity/transaction.h
@@ -713,7 +713,7 @@ int msc_process_uri(Transaction *transaction, const char *uri,
     const char *protocol, const char *http_version);
 
 /** @ingroup ModSecurity_C_API */
-const char *msc_get_response_body(Transaction *transaction);
+const char *msc_get_response_body(const Transaction *transaction);
 
 /** @ingroup ModSecurity_C_API */
 size_t msc_get_response_body_length(Transaction *transaction);
diff --git a/src/actions/ctl/rule_remove_by_id.cc b/src/actions/ctl/rule_remove_by_id.cc
index 869dc4f9..ff867381 100644
--- a/src/actions/ctl/rule_remove_by_id.cc
+++ b/src/actions/ctl/rule_remove_by_id.cc
@@ -84,10 +84,10 @@ bool RuleRemoveById::init(std::string *error) {
 }
 
 bool RuleRemoveById::evaluate(RuleWithActions *rule, Transaction *transaction) {
-    for (auto &i : m_ids) {
+    for (const auto &i : m_ids) {
         transaction->m_ruleRemoveById.push_back(i);
     }
-    for (auto &i : m_ranges) {
+    for (const auto &i : m_ranges) {
         transaction->m_ruleRemoveByIdRange.push_back(i);
     }
 
diff --git a/src/actions/transformations/hex_decode.cc b/src/actions/transformations/hex_decode.cc
index 1b43b6cd..ed3c76f6 100644
--- a/src/actions/transformations/hex_decode.cc
+++ b/src/actions/transformations/hex_decode.cc
@@ -26,7 +26,7 @@ static inline int inplace(std::string &value) {
 
     const auto len = value.length();
     auto d = reinterpret_cast<unsigned char *>(value.data());
-    const auto data = d;
+    const auto *data = d;
 
     for (int i = 0; i <= len - 2; i += 2) {
         *d++ = utils::string::x2c(&data[i]);
diff --git a/src/actions/transformations/html_entity_decode.cc b/src/actions/transformations/html_entity_decode.cc
index 8a0cc3e9..9c6b989d 100644
--- a/src/actions/transformations/html_entity_decode.cc
+++ b/src/actions/transformations/html_entity_decode.cc
@@ -118,7 +118,7 @@ static inline bool inplace(std::string &value) {
                     j++;
                 }
                 if (j > k) { /* Do we have at least one digit? */
-                    const auto x = reinterpret_cast<const char*>(&input[k]);
+                    const auto *x = reinterpret_cast<const char*>(&input[k]);
 
                     /* Decode the entity. */
                     /* ENH What about others? */
diff --git a/src/actions/transformations/normalise_path.cc b/src/actions/transformations/normalise_path.cc
index 91c04027..5c67ddc1 100644
--- a/src/actions/transformations/normalise_path.cc
+++ b/src/actions/transformations/normalise_path.cc
@@ -29,9 +29,6 @@ bool NormalisePath::transform(std::string &value, const Transaction *trans) cons
  * IMP1 Assumes NUL-terminated
  */
 bool NormalisePath::normalize_path_inplace(std::string &val, const bool win) {
-    unsigned char *src;
-    unsigned char *dst;
-    unsigned char *end;
     int hitroot = 0;
     int done = 0;
     int relative;
@@ -49,13 +46,13 @@ bool NormalisePath::normalize_path_inplace(std::string &val, const bool win) {
      * ENH: Deal with UNC and drive letters?
      */
 
-    src = dst = input;
-    end = input + (input_len - 1);
+    auto src = input;
+    auto dst = input;
+    const auto *end = input + (input_len - 1);
 
     relative = ((*input == '/') || (win && (*input == '\\'))) ? 0 : 1;
     trailing = ((*end == '/') || (win && (*end == '\\'))) ? 1 : 0;
 
-
     while (!done && (src <= end) && (dst <= end)) {
         /* Convert backslash to forward slash on Windows only. */
         if (win) {
@@ -152,7 +149,7 @@ copy:
 
         /* Skip to the last forward slash when multiple are used. */
         if (*src == '/') {
-            unsigned char *oldsrc = src;
+            const unsigned char *oldsrc = src;
 
             while ((src < end)
                 && ((*(src + 1) == '/') || (win && (*(src + 1) == '\\'))) ) {
diff --git a/src/actions/transformations/sql_hex_decode.cc b/src/actions/transformations/sql_hex_decode.cc
index 0ce24087..de0ea26b 100644
--- a/src/actions/transformations/sql_hex_decode.cc
+++ b/src/actions/transformations/sql_hex_decode.cc
@@ -38,7 +38,7 @@ static inline bool inplace(std::string &value) {
 
     auto d = reinterpret_cast<unsigned char*>(value.data());
     const unsigned char *data = d;
-    const auto end = data + value.size();
+    const auto *end = data + value.size();
 
     bool changed = false;
 
diff --git a/src/collection/backend/lmdb.cc b/src/collection/backend/lmdb.cc
index 3fe68061..ffad0c76 100644
--- a/src/collection/backend/lmdb.cc
+++ b/src/collection/backend/lmdb.cc
@@ -559,7 +559,7 @@ void LMDB::resolveMultiMatches(const std::string& var,
                 continue;
             }
 
-            char *a = reinterpret_cast<char *>(key.mv_data);
+            const char *a = reinterpret_cast<char *>(key.mv_data);
             if (strncmp(var.c_str(), a, keySize) == 0) {
                 std::string key_to_insert(reinterpret_cast<char *>(key.mv_data), key.mv_size);
                 l->insert(l->begin(), new VariableValue(&m_name, &key_to_insert, &collectionData.getValue()));
diff --git a/src/engine/lua.cc b/src/engine/lua.cc
index 1bed9044..9313a2ec 100644
--- a/src/engine/lua.cc
+++ b/src/engine/lua.cc
@@ -114,14 +114,14 @@ int Lua::blob_keeper(lua_State *L, const void *p, size_t sz, void *ud) {
 
 
 const char *Lua::blob_reader(lua_State *L, void *ud, size_t *size) {
-    LuaScriptBlob *lsb = static_cast<LuaScriptBlob *>(ud);
+    const LuaScriptBlob *lsb = static_cast<LuaScriptBlob *>(ud);
     const char *data = lsb->read(size);
     return data;
 }
 #endif
 
 
-int Lua::run(Transaction *t, const std::string &str) {
+int Lua::run(Transaction *t, const std::string &str) { // cppcheck-suppress constParameterPointer
 #ifdef WITH_LUA
     std::string luaRet;
     const char *a = NULL;
diff --git a/src/operators/geo_lookup.h b/src/operators/geo_lookup.h
index 187a2f31..81155d61 100644
--- a/src/operators/geo_lookup.h
+++ b/src/operators/geo_lookup.h
@@ -33,7 +33,7 @@ class GeoLookup : public Operator {
 
  protected:
     // cppcheck-suppress functionStatic
-    bool debug(Transaction *transaction, int x, const std::string &a) {
+    bool debug(const Transaction *transaction, int x, const std::string &a) {
         ms_dbg_a(transaction, x, a);
         return true;
     }
diff --git a/src/operators/operator.h b/src/operators/operator.h
index ba94a1b4..636ad5e0 100644
--- a/src/operators/operator.h
+++ b/src/operators/operator.h
@@ -136,7 +136,7 @@ class Operator {
 
     std::string m_match_message;
     bool m_negation;
-    std::string m_op;
+    const std::string m_op;
     std::string m_param;
     std::unique_ptr<RunTimeString> m_string;
     bool m_couldContainsMacro;
diff --git a/src/operators/rbl.cc b/src/operators/rbl.cc
index 35bbc5f9..4b06f337 100644
--- a/src/operators/rbl.cc
+++ b/src/operators/rbl.cc
@@ -73,8 +73,8 @@ std::string Rbl::mapIpToAddress(const std::string &ipStr, Transaction *trans) co
 
 
 void Rbl::futherInfo_httpbl(struct sockaddr_in *sin, const std::string &ipStr,
-    Transaction *trans) {
-    char *respBl;
+    const Transaction *trans) {
+    const char *respBl;
     int first, days, score, type;
 #ifndef NO_LOGS
     std::string ptype;
@@ -131,7 +131,7 @@ void Rbl::futherInfo_httpbl(struct sockaddr_in *sin, const std::string &ipStr,
 
 
 void Rbl::futherInfo_spamhaus(unsigned int high8bits, const std::string &ipStr,
-    Transaction *trans) {
+    const Transaction *trans) {
     switch (high8bits) {
         case 2:
         case 3:
@@ -158,7 +158,7 @@ void Rbl::futherInfo_spamhaus(unsigned int high8bits, const std::string &ipStr,
 
 
 void Rbl::futherInfo_uribl(unsigned int high8bits, const std::string &ipStr,
-    Transaction *trans) {
+    const Transaction *trans) {
     switch (high8bits) {
         case 2:
             ms_dbg_a(trans, 4, "RBL lookup of " + ipStr + " succeeded (BLACK).");
@@ -185,7 +185,7 @@ void Rbl::futherInfo_uribl(unsigned int high8bits, const std::string &ipStr,
 
 
 void Rbl::furtherInfo(struct sockaddr_in *sin, const std::string &ipStr,
-    Transaction *trans, RblProvider provider) {
+    const Transaction *trans, RblProvider provider) {
     unsigned int high8bits = sin->sin_addr.s_addr >> 24;
 
     switch (provider) {
diff --git a/src/operators/rbl.h b/src/operators/rbl.h
index e7d9538c..26fd483c 100644
--- a/src/operators/rbl.h
+++ b/src/operators/rbl.h
@@ -88,13 +88,13 @@ class Rbl : public Operator {
     std::string mapIpToAddress(const std::string &ipStr, Transaction *trans) const;
 
     static void futherInfo_httpbl(struct sockaddr_in *sin, const std::string &ipStr,
-        Transaction *trans);
+        const Transaction *trans);
     static void futherInfo_spamhaus(unsigned int high8bits, const std::string &ipStr,
-        Transaction *trans);
+        const Transaction *trans);
     static void futherInfo_uribl(unsigned int high8bits, const std::string &ipStr,
-        Transaction *trans);
+        const Transaction *trans);
     static void furtherInfo(struct sockaddr_in *sin, const std::string &ipStr,
-        Transaction *trans, RblProvider provider);
+        const Transaction *trans, RblProvider provider);
 
  private:
     std::string m_service;
diff --git a/src/operators/validate_dtd.h b/src/operators/validate_dtd.h
index d35d7b35..e69e280a 100644
--- a/src/operators/validate_dtd.h
+++ b/src/operators/validate_dtd.h
@@ -62,7 +62,7 @@ class ValidateDTD : public Operator {
 
 
     static void error_runtime(void *ctx, const char *msg, ...) {
-        Transaction *t = reinterpret_cast<Transaction *>(ctx);
+        const Transaction *t = reinterpret_cast<Transaction *>(ctx);
         char buf[1024];
         std::string s;
         va_list args;
@@ -79,7 +79,7 @@ class ValidateDTD : public Operator {
 
 
     static void warn_runtime(void *ctx, const char *msg, ...) {
-        Transaction *t = reinterpret_cast<Transaction *>(ctx);
+        const Transaction *t = reinterpret_cast<Transaction *>(ctx);
         char buf[1024];
         std::string s;
         va_list args;
@@ -95,7 +95,7 @@ class ValidateDTD : public Operator {
     }
 
 
-    static void null_error(void *ctx, const char *msg, ...) {
+    static void null_error(void *ctx, const char *msg, ...) { // cppcheck-suppress[constParameterPointer,constParameterCallback]
     }
 
  private:
diff --git a/src/operators/validate_schema.h b/src/operators/validate_schema.h
index f681b853..510cfc65 100644
--- a/src/operators/validate_schema.h
+++ b/src/operators/validate_schema.h
@@ -75,7 +75,7 @@ class ValidateSchema : public Operator {
 
 
     static void error_runtime(void *ctx, const char *msg, ...) {
-        Transaction *t = reinterpret_cast<Transaction *>(ctx);
+        const Transaction *t = reinterpret_cast<Transaction *>(ctx);
         char buf[1024];
         std::string s;
         va_list args;
@@ -92,7 +92,7 @@ class ValidateSchema : public Operator {
 
 
     static void warn_runtime(void *ctx, const char *msg, ...) {
-        Transaction *t = reinterpret_cast<Transaction *>(ctx);
+        const Transaction *t = reinterpret_cast<Transaction *>(ctx);
         char buf[1024];
         std::string s;
         va_list args;
@@ -107,7 +107,7 @@ class ValidateSchema : public Operator {
         ms_dbg_a(t, 4, s);
     }
 
-    static void null_error(void *ctx, const char *msg, ...) {
+    static void null_error(void *ctx, const char *msg, ...) { // cppcheck-suppress[constParameterPointer,constParameterCallback]
     }
 
  private:
diff --git a/src/operators/verify_cpf.cc b/src/operators/verify_cpf.cc
index b012eac8..3163109c 100644
--- a/src/operators/verify_cpf.cc
+++ b/src/operators/verify_cpf.cc
@@ -38,7 +38,7 @@ int VerifyCPF::convert_to_int(const char c) {
 }
 
 
-bool VerifyCPF::verify(const char *cpfnumber, int len) {
+bool VerifyCPF::verify(const char *cpfnumber, int len) const {
     int factor, part_1, part_2, var_len = len;
     unsigned int sum = 0, i = 0, cpf_len = 11, c;
     int cpf[11];
diff --git a/src/operators/verify_cpf.h b/src/operators/verify_cpf.h
index a4ff4c22..22e26026 100644
--- a/src/operators/verify_cpf.h
+++ b/src/operators/verify_cpf.h
@@ -45,7 +45,7 @@ class VerifyCPF : public Operator {
         const std::string& input,
         RuleMessage &ruleMessage) override;
 
-    bool verify(const char *ssnumber, int len);
+    bool verify(const char *ssnumber, int len) const;
 
  private:
     static int convert_to_int(const char c);
diff --git a/src/operators/verify_svnr.cc b/src/operators/verify_svnr.cc
index f869411d..210e9201 100644
--- a/src/operators/verify_svnr.cc
+++ b/src/operators/verify_svnr.cc
@@ -24,7 +24,7 @@ int VerifySVNR::convert_to_int(const char c) {
 }
 
 
-bool VerifySVNR::verify(const char *svnrnumber, int len) {
+bool VerifySVNR::verify(const char *svnrnumber, int len) const {
     int var_len = len;
     int sum = 0;
     unsigned int i = 0, svnr_len = 10;
diff --git a/src/operators/verify_svnr.h b/src/operators/verify_svnr.h
index aad3d791..ee693346 100644
--- a/src/operators/verify_svnr.h
+++ b/src/operators/verify_svnr.h
@@ -31,7 +31,7 @@ class VerifySVNR : public Operator {
         const std::string& input,
         RuleMessage &ruleMessage) override;
 
-    bool verify(const char *ssnumber, int len);
+    bool verify(const char *ssnumber, int len) const;
 
  private:
     std::unique_ptr<Regex> m_re;
diff --git a/src/parser/driver.cc b/src/parser/driver.cc
index a42942fb..b86f4c57 100644
--- a/src/parser/driver.cc
+++ b/src/parser/driver.cc
@@ -107,9 +107,9 @@ int Driver::addSecRule(std::unique_ptr<RuleWithActions> r) {
     }
 
     for (int i = 0; i < modsecurity::Phases::NUMBER_OF_PHASES; i++) {
-        Rules *rules = m_rulesSetPhases[i];
+        const Rules *rules = m_rulesSetPhases[i];
         for (int j = 0; j < rules->size(); j++) {
-            RuleWithOperator *lr = dynamic_cast<RuleWithOperator *>(rules->at(j).get());
+            const RuleWithOperator *lr = dynamic_cast<RuleWithOperator *>(rules->at(j).get());
             if (lr && lr->m_ruleId == rule->m_ruleId) {
                 m_parserError << "Rule id: " << std::to_string(rule->m_ruleId) \
                     << " is duplicated" << std::endl;
diff --git a/src/request_body_processor/json.cc b/src/request_body_processor/json.cc
index 585976b4..f56704ef 100644
--- a/src/request_body_processor/json.cc
+++ b/src/request_body_processor/json.cc
@@ -131,7 +131,7 @@ int JSON::addArgument(const std::string& value) {
     std::string path;
 
     for (size_t i =  0; i < m_containers.size(); i++) {
-        JSONContainerArray *a = dynamic_cast<JSONContainerArray *>(
+        const JSONContainerArray *a = dynamic_cast<JSONContainerArray *>(
             m_containers[i]);
         path = path + m_containers[i]->m_name;
         if (a != NULL) {
diff --git a/src/request_body_processor/json.h b/src/request_body_processor/json.h
index 19c469ee..961ea94e 100644
--- a/src/request_body_processor/json.h
+++ b/src/request_body_processor/json.h
@@ -79,7 +79,7 @@ class JSON {
     static int yajl_end_array(void *ctx);
 
     bool isPreviousArray() const {
-        JSONContainerArray *prev = NULL;
+        const JSONContainerArray *prev = NULL;
         if (m_containers.size() < 1) {
             return false;
         }
diff --git a/src/request_body_processor/xml.h b/src/request_body_processor/xml.h
index 1d29f62f..fa8dc786 100644
--- a/src/request_body_processor/xml.h
+++ b/src/request_body_processor/xml.h
@@ -53,7 +53,7 @@ class XML {
     static xmlParserInputBufferPtr unloadExternalEntity(const char *URI,
         xmlCharEncoding enc);
 
-    static void null_error(void *ctx, const char *msg, ...) {
+    static void null_error(void *ctx, const char *msg, ...) { // cppcheck-suppress[constParameterPointer,constParameterCallback]
     }
 
 
diff --git a/src/rule_with_actions.cc b/src/rule_with_actions.cc
index 67961155..f6642b67 100644
--- a/src/rule_with_actions.cc
+++ b/src/rule_with_actions.cc
@@ -363,7 +363,7 @@ void RuleWithActions::executeTransformations(
                        std::make_shared<std::string>(path));
     }
 
-    for (Action *a : m_transformations) {
+    for (const Action *a : m_transformations) {
         if (a->m_isNone) {
             none++;
         }
@@ -457,7 +457,7 @@ bool RuleWithActions::containsMsg(const std::string& name, Transaction *t) {
 
 
 std::vector<actions::Action *> RuleWithActions::getActionsByName(const std::string& name,
-    Transaction *trans) {
+    const Transaction *trans) {
     std::vector<actions::Action *> ret;
     for (auto &z : m_actionsRuntimePos) {
         if (*z->m_name.get() == name) {
diff --git a/src/rule_with_operator.cc b/src/rule_with_operator.cc
index a3e35bf0..acabde39 100644
--- a/src/rule_with_operator.cc
+++ b/src/rule_with_operator.cc
@@ -176,7 +176,7 @@ inline void RuleWithOperator::getFinalVars(variables::Variables *vars,
         }
         if (std::find_if(trans->m_ruleRemoveTargetById.begin(),
                 trans->m_ruleRemoveTargetById.end(),
-                [&, variable, this](std::pair<int, std::string> &m) -> bool {
+                [&, variable, this](const auto &m) -> bool {
                     return m.first == m_ruleId
                         && m.second == *variable->m_fullName.get();
                 }) != trans->m_ruleRemoveTargetById.end()) {
@@ -185,7 +185,7 @@ inline void RuleWithOperator::getFinalVars(variables::Variables *vars,
         if (std::find_if(trans->m_ruleRemoveTargetByTag.begin(),
                     trans->m_ruleRemoveTargetByTag.end(),
                     [&, variable, trans, this](
-                        std::pair<std::string, std::string> &m) -> bool {
+                        const auto &m) -> bool {
                         return containsTag(m.first, trans)
                             && m.second == *variable->m_fullName.get();
                     }) != trans->m_ruleRemoveTargetByTag.end()) {
@@ -203,7 +203,7 @@ inline void RuleWithOperator::getFinalVars(variables::Variables *vars,
 bool RuleWithOperator::evaluate(Transaction *trans,
     RuleMessage &ruleMessage) {
     bool globalRet = false;
-    variables::Variables *variables = this->m_variables;
+    const variables::Variables *variables = this->m_variables; // cppcheck-suppress unreadVariable ; false positive
     bool recursiveGlobalRet;
     bool containsBlock = hasBlockAction();
     std::string eparam;
@@ -270,23 +270,23 @@ bool RuleWithOperator::evaluate(Transaction *trans,
             if (exclusion.contains(v) ||
                 std::find_if(trans->m_ruleRemoveTargetById.begin(),
                     trans->m_ruleRemoveTargetById.end(),
-                    [&, v, this](std::pair<int, std::string> &m) -> bool {
+                    [&, v, this](const auto &m) -> bool {
                         return m.first == m_ruleId && m.second == v->getKeyWithCollection();
                     }) != trans->m_ruleRemoveTargetById.end()
             ) {
                 delete v;
-                v = NULL;
+                v = nullptr;
                 continue;
             }
             if (exclusion.contains(v) ||
                 std::find_if(trans->m_ruleRemoveTargetByTag.begin(),
                     trans->m_ruleRemoveTargetByTag.end(),
-                    [&, v, trans, this](std::pair<std::string, std::string> &m) -> bool {
+                    [&, v, trans, this](const auto &m) -> bool {
                         return containsTag(m.first, trans) && m.second == v->getKeyWithCollection();
                     }) != trans->m_ruleRemoveTargetByTag.end()
             ) {
                 delete v;
-                v = NULL;
+                v = nullptr;
                 continue;
             }
 
@@ -360,7 +360,7 @@ end_exec:
 }
 
 
-std::string RuleWithOperator::getOperatorName() const { return m_operator->m_op; }
+const std::string& RuleWithOperator::getOperatorName() const { return m_operator->m_op; }
 
 
 }  // namespace modsecurity
diff --git a/src/rules_exceptions.cc b/src/rules_exceptions.cc
index 71cf28c2..1545571c 100644
--- a/src/rules_exceptions.cc
+++ b/src/rules_exceptions.cc
@@ -254,11 +254,11 @@ bool RulesExceptions::merge(RulesExceptions *from) {
                     p.second));
     }
 
-    for (auto &p : from->m_remove_rule_by_msg) {
+    for (const auto &p : from->m_remove_rule_by_msg) {
         m_remove_rule_by_msg.push_back(p);
     }
 
-    for (auto &p : from->m_remove_rule_by_tag) {
+    for (const auto &p : from->m_remove_rule_by_tag) {
         m_remove_rule_by_tag.push_back(p);
     }
 
diff --git a/src/rules_set.cc b/src/rules_set.cc
index 025abe69..19f31d89 100644
--- a/src/rules_set.cc
+++ b/src/rules_set.cc
@@ -266,7 +266,7 @@ extern "C" RulesSet *msc_create_rules_set(void) {
 }
 
 
-extern "C" void msc_rules_dump(RulesSet *rules) {
+extern "C" void msc_rules_dump(const RulesSet *rules) {
     rules->dump();
 }
 
diff --git a/src/rules_set_properties.cc b/src/rules_set_properties.cc
index 80078b3d..ab4bdeda 100644
--- a/src/rules_set_properties.cc
+++ b/src/rules_set_properties.cc
@@ -30,9 +30,9 @@ void ConfigUnicodeMap::loadConfig(std::string f, double configCodePage,
     RulesSetProperties *driver, std::string *errg) {
     char *buf = NULL;
     char *hmap = NULL;
-    char *p = NULL;
+    const char *p = NULL;
     char *savedptr = NULL;
-    char *ucode = NULL;
+    const char *ucode = NULL;
     int code = 0;
     int found = 0;
     int length = 0;
diff --git a/src/transaction.cc b/src/transaction.cc
index f5ded524..55e2dd3c 100644
--- a/src/transaction.cc
+++ b/src/transaction.cc
@@ -1175,7 +1175,7 @@ int Transaction::processResponseBody() {
 int Transaction::appendResponseBody(const unsigned char *buf, size_t len) {
     int current_size = this->m_responseBody.tellp();
 
-    std::set<std::string> &bi = \
+    const std::set<std::string> &bi = \
         this->m_rules->m_responseBodyTypeToBeInspected.m_value;
     auto t = bi.find(m_variableResponseContentType.m_value);
     if (t == bi.end() && bi.empty() == false) {
@@ -1677,7 +1677,7 @@ std::string Transaction::toJSON(int parts) {
             strlen("components"));
 
         yajl_gen_array_open(g);
-        for (auto a : m_rules->m_components) {
+        for (const auto &a : m_rules->m_components) {
             yajl_gen_string(g,
                 reinterpret_cast<const unsigned char*>
                     (a.c_str()), a.length());
@@ -2197,7 +2197,7 @@ extern "C" void msc_intervention_cleanup(ModSecurityIntervention *it) {
  * @retval NULL Nothing was updated.
  *
  */
-extern "C" const char *msc_get_response_body(Transaction *transaction) {
+extern "C" const char *msc_get_response_body(const Transaction *transaction) {
     return transaction->getResponseBody();
 }
 
diff --git a/src/utils/regex.cc b/src/utils/regex.cc
index 5facd2b1..731ffc97 100644
--- a/src/utils/regex.cc
+++ b/src/utils/regex.cc
@@ -154,7 +154,7 @@ std::list<SMatch> Regex::searchAll(const std::string& s) const {
             rc = pcre2_match(m_pc, pcre2_s, s.length(),
                             offset, PCRE2_NO_JIT, match_data, NULL);
         }
-        PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
+        const PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
 #else
     const char *subject = s.c_str();
     int ovector[OVECCOUNT];
@@ -207,7 +207,7 @@ RegexResult Regex::searchOneMatch(const std::string& s, std::vector<SMatchCaptur
     if (m_pcje != 0 || rc == PCRE2_ERROR_JIT_STACKLIMIT) {
         rc = pcre2_match(m_pc, pcre2_s, s.length(), 0, PCRE2_NO_JIT, match_data, match_context);
     }
-    PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
+    const PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
 #else
     const char *subject = s.c_str();
     int ovector[OVECCOUNT];
@@ -261,7 +261,7 @@ RegexResult Regex::searchGlobal(const std::string& s, std::vector<SMatchCapture>
         }
         int rc = pcre2_match(m_pc, pcre2_s, s.length(),
                             startOffset, pcre2_options, match_data, match_context);
-        PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
+        const PCRE2_SIZE *ovector = pcre2_get_ovector_pointer(match_data);
 
 #else
     const char *subject = s.c_str();
diff --git a/src/variables/env.cc b/src/variables/env.cc
index bf40954a..95f0f766 100644
--- a/src/variables/env.cc
+++ b/src/variables/env.cc
@@ -54,7 +54,7 @@ void Env::evaluate(Transaction *transaction,
     }
 
     const auto hasName = m_name.length() > 0;
-    for (auto& x : transaction->m_variableEnvs) {
+    for (const auto& x : transaction->m_variableEnvs) {
 #ifndef WIN32
         if (hasName && x.first != m_name) {
 #else
diff --git a/src/variables/variable.cc b/src/variables/variable.cc
index 043b8ede..caf8f6fd 100644
--- a/src/variables/variable.cc
+++ b/src/variables/variable.cc
@@ -48,23 +48,23 @@ Variable::Variable(const std::string &name)
 }
 
 
-Variable::Variable(Variable *var) :
+Variable::Variable(const Variable *var) :
     m_name(var->m_name),
     m_collectionName(var->m_collectionName),
     m_fullName(var->m_fullName) { }
 
 
-void Variable::addsKeyExclusion(Variable *v) {
+void Variable::addsKeyExclusion(const Variable *v) {
     std::unique_ptr<KeyExclusion> r;
-    VariableModificatorExclusion *ve = \
-        dynamic_cast<VariableModificatorExclusion *>(v);
-    VariableRegex *vr;
+    const auto *ve = \
+        dynamic_cast<const VariableModificatorExclusion *>(v);
+    const VariableRegex *vr;
 
     if (!ve) {
         return;
     }
 
-    vr = dynamic_cast<VariableRegex *>(ve->m_base.get());
+    vr = dynamic_cast<const VariableRegex *>(ve->m_base.get());
 
     if (vr == NULL) {
         r.reset(new KeyExclusionString(v->m_name));
@@ -76,12 +76,12 @@ void Variable::addsKeyExclusion(Variable *v) {
 }
 
 
-std::string operator+(const std::string &a, Variable *v) {
+std::string operator+(const std::string &a, const Variable *v) {
     return a + *v->m_fullName.get();
 }
 
 
-std::string operator+(const std::string &a, Variables *v) {
+std::string operator+(const std::string &a, const Variables *v) {
     std::string test;
     for (const auto &b : *v) {
         if (test.empty()) {
diff --git a/src/variables/variable.h b/src/variables/variable.h
index 2d8c6ec0..5d740e10 100644
--- a/src/variables/variable.h
+++ b/src/variables/variable.h
@@ -132,7 +132,7 @@ class KeyExclusionRegex : public KeyExclusion {
 
 class KeyExclusionString : public KeyExclusion {
  public:
-    explicit KeyExclusionString(std::string &a)
+    explicit KeyExclusionString(const std::string &a)
         : m_key(utils::string::toupper(a)) { }
 
     ~KeyExclusionString() override { }
@@ -589,7 +589,7 @@ class VariableMonkeyResolution {
 class Variable : public VariableMonkeyResolution {
  public:
     explicit Variable(const std::string &name);
-    explicit Variable(Variable *_name);
+    explicit Variable(const Variable *_name);
     virtual ~Variable() { }
 
 
@@ -608,7 +608,7 @@ class Variable : public VariableMonkeyResolution {
     }
 
 
-    void addsKeyExclusion(Variable *v);
+    void addsKeyExclusion(const Variable *v);
 
 
     bool operator==(const Variable& b) const {
@@ -718,8 +718,8 @@ class VariableModificatorCount : public Variable {
 };
 
 
-std::string operator+(const std::string &a, modsecurity::variables::Variable *v);
-std::string operator+(const std::string &a, modsecurity::variables::Variables *v);
+std::string operator+(const std::string &a, const modsecurity::variables::Variable *v);
+std::string operator+(const std::string &a, const modsecurity::variables::Variables *v);
 
 
 }  // namespace variables
diff --git a/test/benchmark/benchmark.cc b/test/benchmark/benchmark.cc
index 8b36d368..a502150e 100644
--- a/test/benchmark/benchmark.cc
+++ b/test/benchmark/benchmark.cc
@@ -44,7 +44,7 @@ char rules_file[] = "basic_rules.conf";
 
 const char* const help_message = "Usage: benchmark [num_iterations|-h|-?|--help]";
 
-int main(int argc, char *argv[]) {
+int main(int argc, const char *argv[]) {
 
     unsigned long long NUM_REQUESTS(1000000);
 
diff --git a/test/common/modsecurity_test.cc b/test/common/modsecurity_test.cc
index 1e0585d4..21af285d 100644
--- a/test/common/modsecurity_test.cc
+++ b/test/common/modsecurity_test.cc
@@ -89,7 +89,7 @@ template <class T>
 void
 ModSecurityTest<T>::load_tests(const std::string &path) {
     DIR *dir;
-    struct dirent *ent;
+    const struct dirent *ent;
     struct stat buffer;
 
     if ((dir = opendir(path.c_str())) == nullptr) {
diff --git a/test/optimization/optimization.cc b/test/optimization/optimization.cc
index 19298b0b..7edc44fa 100644
--- a/test/optimization/optimization.cc
+++ b/test/optimization/optimization.cc
@@ -54,7 +54,7 @@ int main(int argc, char **argv) {
     }
 
 
-    for (auto &x : files) {
+    for (const auto &x : files) {
         std::cout << "Loading file: " << x << std::endl;
         if (modsecRules->loadFromUri(x.c_str()) < 0) {
             std::cout << "Not able to load the rules" << std::endl;
@@ -96,8 +96,8 @@ int main(int argc, char **argv) {
                 }
             }
 
-            if (auto rwo = dynamic_cast<modsecurity::RuleWithOperator *>(z.get())) {
-                std::string op = rwo->getOperatorName();
+            if (const auto *rwo = dynamic_cast<modsecurity::RuleWithOperator *>(z.get())) {
+                const auto op = rwo->getOperatorName();
                 if (operators.count(op) > 0) {
                     operators[op] = 1 + operators[op];
                 } else {
diff --git a/test/regression/regression.cc b/test/regression/regression.cc
index 6d7b9dc3..f8acffb1 100644
--- a/test/regression/regression.cc
+++ b/test/regression/regression.cc
@@ -26,6 +26,7 @@
 #include <string>
 #include <list>
 #include <algorithm>
+#include <cassert>
 
 #include "modsecurity/rules_set.h"
 #include "modsecurity/modsecurity.h"
@@ -110,8 +111,8 @@ void actions(ModSecurityTestResults<RegressionTest> *r,
     }
 }
 
-void perform_unit_test(ModSecurityTest<RegressionTest> *test,
-    std::vector<std::unique_ptr<RegressionTest>> &tests,
+void perform_unit_test(const ModSecurityTest<RegressionTest> &test,
+    const std::vector<std::unique_ptr<RegressionTest>> &tests,
     ModSecurityTestResults<RegressionTestResult> *res, int *count)
 {
     for (auto &t : tests) {
@@ -131,7 +132,7 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
             filename = t->filename;
         }
 
-        if (!test->m_automake_output) {
+        if (!test.m_automake_output) {
             std::cout << std::setw(3) << std::right <<
                 std::to_string(*count) << " ";
             std::cout << std::setw(50) << std::left << filename;
@@ -139,7 +140,7 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
         }
 
         if (t->enabled == 0) {
-            if (test->m_automake_output) {
+            if (test.m_automake_output) {
                 std::cout << ":test-result: SKIP" << filename \
                     << ":" << t->name << std::endl;
             } else {
@@ -173,7 +174,7 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
             testRes->reason << KCYN << "compiled with support " << std::endl;
             testRes->reason << KCYN << "to: " << t->resource << std::endl;
             testRes->reason << RESET << std::endl;
-            if (test->m_automake_output) {
+            if (test.m_automake_output) {
                 std::cout << ":test-result: SKIP " << filename \
                     << ":" << t->name << std::endl;
             } else {
@@ -192,7 +193,7 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
                  * Not expecting any error, thus return the error to
                  * the user.
                  */
-                if (test->m_automake_output) {
+                if (test.m_automake_output) {
                     std::cout << ":test-result: FAIL " << filename \
                         << ":" << t->name << ":" << *count << std::endl;
                 } else {
@@ -213,7 +214,7 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
             const auto s = context.m_modsec_rules.getParserError();
 
             if (regex_search(s, &match, re)) {
-                if (test->m_automake_output) {
+                if (test.m_automake_output) {
                     std::cout << ":test-result: PASS " << filename \
                         << ":" << t->name << std::endl;
                 } else {
@@ -227,7 +228,7 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
                 continue;
             } else {
                 /* Parser error was expected, but with a different content */
-                if (test->m_automake_output) {
+                if (test.m_automake_output) {
                     std::cout << ":test-result: FAIL " << filename \
                         << ":" << t->name << ":" << *count << std::endl;
                 } else {
@@ -249,7 +250,7 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
         } else {
             /* Parser error was expected but never happened */
             if (t->parser_error.empty() == false) {
-                if (test->m_automake_output) {
+                if (test.m_automake_output) {
                     std::cout << ":test-result: FAIL " << filename \
                         << ":" << t->name << ":" << *count << std::endl;
                 } else {
@@ -318,7 +319,7 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
         const auto *d = static_cast<CustomDebugLog *>(context.m_modsec_rules.m_debugLog);
 
         if (!d->contains(t->debug_log)) {
-            if (test->m_automake_output) {
+            if (test.m_automake_output) {
                 std::cout << ":test-result: FAIL " << filename \
                     << ":" << t->name << ":" << *count << std::endl;
             } else {
@@ -330,7 +331,7 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
                 << t->debug_log + "";
             testRes->passed = false;
         } else if (r.status != t->http_code) {
-            if (test->m_automake_output) {
+            if (test.m_automake_output) {
                 std::cout << ":test-result: FAIL " << filename \
                     << ":" << t->name << ":" << *count << std::endl;
             } else {
@@ -341,7 +342,7 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
                 " got: " + std::to_string(r.status) + "\n";
             testRes->passed = false;
         } else if (!contains(context.m_server_log.str(), t->error_log)) {
-            if (test->m_automake_output) {
+            if (test.m_automake_output) {
                 std::cout << ":test-result: FAIL " << filename \
                     << ":" << t->name << std::endl;
             } else {
@@ -353,7 +354,7 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
                 << t->error_log + "";
             testRes->passed = false;
         } else if (!t->audit_log.empty() && !contains(getAuditLogContent(modsec_transaction.m_rules->m_auditLog->m_path1), t->audit_log)) {
-            if (test->m_automake_output) {
+            if (test.m_automake_output) {
                 std::cout << ":test-result: FAIL " << filename \
                     << ":" << t->name << ":" << *count << std::endl;
             } else {
@@ -365,7 +366,7 @@ void perform_unit_test(ModSecurityTest<RegressionTest> *test,
                 << t->audit_log + "";
             testRes->passed = false;
         } else {
-            if (test->m_automake_output) {
+            if (test.m_automake_output) {
                 std::cout << ":test-result: PASS " << filename \
                     << ":" << t->name << std::endl;
             } else  {
@@ -471,8 +472,8 @@ int main(int argc, char **argv)
         test_number++;
         if ((test.m_test_number == 0)
             || (test_number == test.m_test_number)) {
-            auto &tests = test[a];
-            perform_unit_test(&test, tests, &res, &counter);
+            const auto &tests = test[a];
+            perform_unit_test(test, tests, &res, &counter);
         }
     }
 
diff --git a/test/unit/unit.cc b/test/unit/unit.cc
index 73ba7af6..8bf5954d 100644
--- a/test/unit/unit.cc
+++ b/test/unit/unit.cc
@@ -92,7 +92,7 @@ struct TransformationTest {
         return tfn;
     }
 
-    static UnitTestResult eval(const ItemType &tfn, const UnitTest &t, modsecurity::Transaction &transaction) {
+    static UnitTestResult eval(const ItemType &tfn, const UnitTest &t, const modsecurity::Transaction &transaction) {
         auto ret = t.input;
         tfn.transform(ret, &transaction);
         return {1, ret};
diff --git a/test/unit/unit_test.cc b/test/unit/unit_test.cc
index b0060732..d7c86c53 100644
--- a/test/unit/unit_test.cc
+++ b/test/unit/unit_test.cc
@@ -75,7 +75,7 @@ void json2bin(std::string *str) {
 }
 
 
-std::string UnitTest::print() {
+std::string UnitTest::print() const {
     std::stringstream i;
 
     i << KRED << "Test failed." << RESET;
diff --git a/test/unit/unit_test.h b/test/unit/unit_test.h
index 81d99d14..326a16c9 100644
--- a/test/unit/unit_test.h
+++ b/test/unit/unit_test.h
@@ -35,7 +35,7 @@ class UnitTest {
  public:
     static UnitTest *from_yajl_node(const yajl_val &);
 
-    std::string print();
+    std::string print() const;
 
     std::string param;
     std::string input;