diff --git a/apache2/msc_crypt.c b/apache2/msc_crypt.c
index c7fd58e1..c1c9c4c2 100644
--- a/apache2/msc_crypt.c
+++ b/apache2/msc_crypt.c
@@ -1103,7 +1103,7 @@ int inject_hashed_response_body(modsec_rec *msr, int elts) {
         memcpy(msr->stream_output_data, xmlOutputBufferGetContent(output_buf), msr->stream_output_length);
 
         if (msr->txcfg->debuglog_level >= 4)
-            msr_log(msr, 4, "inject_hashed_response_body: Copying XML tree from CONTENT to stream buffer [%d] bytes.", xmlOutputBufferGetSize(output_buf));
+            msr_log(msr, 4, "inject_hashed_response_body: Copying XML tree from CONTENT to stream buffer [%zu] bytes.", xmlOutputBufferGetSize(output_buf));
 
     } else {
 
@@ -1132,7 +1132,7 @@ int inject_hashed_response_body(modsec_rec *msr, int elts) {
         memcpy(msr->stream_output_data, xmlOutputBufferGetContent(output_buf), msr->stream_output_length);
 
         if (msr->txcfg->debuglog_level >= 4)
-            msr_log(msr, 4, "inject_hashed_response_body: Copying XML tree from CONV to stream buffer [%d] bytes.", xmlOutputBufferGetSize(output_buf));
+            msr_log(msr, 4, "inject_hashed_response_body: Copying XML tree from CONV to stream buffer [%zu] bytes.", xmlOutputBufferGetSize(output_buf));
 
     }
 
@@ -1379,7 +1379,7 @@ char *do_hash_link(modsec_rec *msr, char *link, int type)  {
             relative_link = relative_uri+1;
 
             if (msr->txcfg->debuglog_level >= 4)    {
-                msr_log(msr, 4, "Signing data [%s] size %d", relative_link, strlen(relative_link));
+                msr_log(msr, 4, "Signing data [%s] size %zu", relative_link, strlen(relative_link));
                 }
 
             if(msr->txcfg->crypto_key_add == HASH_KEYONLY)
diff --git a/apache2/msc_multipart.c b/apache2/msc_multipart.c
index 4afd5c75..88eff9b7 100644
--- a/apache2/msc_multipart.c
+++ b/apache2/msc_multipart.c
@@ -227,7 +227,7 @@ static int multipart_parse_content_disposition(modsec_rec *msr, char *c_d_value)
                 p--;
                 if(*p == '\'' || *p == '\"') {
                     if (msr->txcfg->debuglog_level >= 9) {
-                        msr_log(msr, 9, "Multipart: Invalid quoting detected: %s length %d bytes",
+                        msr_log(msr, 9, "Multipart: Invalid quoting detected: %s length %zu bytes",
                                 log_escape_nq(msr->mp, p), strlen(p));
                     }
                     msr->mpd->flag_invalid_quoting = 1;
diff --git a/apache2/re_operators.c b/apache2/re_operators.c
index c15b83be..1dcd76db 100644
--- a/apache2/re_operators.c
+++ b/apache2/re_operators.c
@@ -843,7 +843,7 @@ static int msre_op_validateHash_execute(modsec_rec *msr, msre_rule *rule, msre_v
 
             nlink = apr_pstrmemdup(msr->mp, target, strlen(target) - strlen(valid) - 1);
 
-            msr_log(msr, 9, "Validating URI %s size %d",nlink,strlen(nlink));
+            msr_log(msr, 9, "Validating URI %s size %zu",nlink,strlen(nlink));
 
             hash_link = do_hash_link(msr, (char *)nlink, HASH_ONLY);