diff --git a/src/actions/set_sid.cc b/src/actions/set_sid.cc
index 940e7dba..017b4fe9 100644
--- a/src/actions/set_sid.cc
+++ b/src/actions/set_sid.cc
@@ -47,6 +47,7 @@ bool SetSID::evaluate(Rule *rule, Transaction *t) {
 #endif
 
     t->m_collections.m_session_collection_key = colNameExpanded;
+    t->m_collections.storeOrUpdateFirst("SESSIONID", colNameExpanded);
 
     return true;
 }
diff --git a/src/parser/seclang-scanner.ll b/src/parser/seclang-scanner.ll
index 2e23b63b..884715d5 100755
--- a/src/parser/seclang-scanner.ll
+++ b/src/parser/seclang-scanner.ll
@@ -116,7 +116,7 @@ OPERATOR_GEOIP  (?i:@geoLookup)
 TRANSFORMATION  t:(?i:(cmdLine|sha1|hexEncode|lowercase|urlDecodeUni|urlDecode|none|compressWhitespace|removeWhitespace|replaceNulls|removeNulls|htmlEntityDecode|jsDecode|cssDecode|trim|normalizePathWin|normalisePathWin|normalisePath|length|utf8toUnicode|urldecode|removeCommentsChar|removeComments|replaceComments))
 
 
-VARIABLE (?i:(RESOURCE|ARGS_COMBINED_SIZE|ARGS_GET_NAMES|ARGS_POST_NAMES|FILES_COMBINED_SIZE|FULL_REQUEST_LENGTH|REQUEST_BODY_LENGTH|REQUEST_URI_RAW|UNIQUE_ID|SERVER_PORT|SERVER_ADDR|REMOTE_PORT|REMOTE_HOST|MULTIPART_STRICT_ERROR|PATH_INFO|MULTIPART_CRLF_LF_LINES|MATCHED_VAR_NAME|MATCHED_VAR|INBOUND_DATA_ERROR|OUTBOUND_DATA_ERROR|FULL_REQUEST|AUTH_TYPE|ARGS_NAMES|REMOTE_ADDR|REQUEST_BASENAME|REQUEST_BODY|REQUEST_FILENAME|REQUEST_HEADERS_NAMES|REQUEST_METHOD|REQUEST_PROTOCOL|REQUEST_URI|RESPONSE_BODY|RESPONSE_CONTENT_LENGTH|RESPONSE_CONTENT_TYPE|RESPONSE_HEADERS_NAMES|RESPONSE_PROTOCOL|RESPONSE_STATUS|REQBODY_PROCESSOR))
+VARIABLE (?i:(RESOURCE|ARGS_COMBINED_SIZE|ARGS_GET_NAMES|ARGS_POST_NAMES|FILES_COMBINED_SIZE|FULL_REQUEST_LENGTH|REQUEST_BODY_LENGTH|REQUEST_URI_RAW|UNIQUE_ID|SERVER_PORT|SERVER_ADDR|REMOTE_PORT|REMOTE_HOST|MULTIPART_STRICT_ERROR|PATH_INFO|MULTIPART_CRLF_LF_LINES|MATCHED_VAR_NAME|MATCHED_VAR|INBOUND_DATA_ERROR|OUTBOUND_DATA_ERROR|FULL_REQUEST|AUTH_TYPE|ARGS_NAMES|REMOTE_ADDR|REQUEST_BASENAME|REQUEST_BODY|REQUEST_FILENAME|REQUEST_HEADERS_NAMES|REQUEST_METHOD|REQUEST_PROTOCOL|REQUEST_URI|RESPONSE_BODY|RESPONSE_CONTENT_LENGTH|RESPONSE_CONTENT_TYPE|RESPONSE_HEADERS_NAMES|RESPONSE_PROTOCOL|RESPONSE_STATUS|REQBODY_PROCESSOR|SESSIONID))
 VARIABLE_COL (?i:(SESSION|GLOBAL|ARGS_POST|ARGS_GET|ARGS|FILES_SIZES|FILES_NAMES|FILES_TMP_CONTENT|MULTIPART_FILENAME|MULTIPART_NAME|MATCHED_VARS_NAMES|MATCHED_VARS|FILES|QUERY_STRING|REQUEST_COOKIES|REQUEST_HEADERS|RESPONSE_HEADERS|GEO|IP|XML|REQUEST_COOKIES_NAMES))
 
 VARIABLE_TX (?i:TX)
diff --git a/test/test-cases/regression/variable-SESSIONID.json b/test/test-cases/regression/variable-SESSIONID.json
new file mode 100644
index 00000000..1bc713a3
--- /dev/null
+++ b/test/test-cases/regression/variable-SESSIONID.json
@@ -0,0 +1,72 @@
+[
+  {
+    "enabled":1,
+    "version_min":300000,
+    "title":"Testing SESSIONID variable (1/2)",
+    "expected":{
+      "debug_log": "Target value: \"rAAAAAAA2t5uvjq435r4q7ib3vtdjq1202\""
+    },
+    "client":{
+      "ip":"200.249.12.31",
+      "port":123
+    },
+    "request":{
+      "headers":{
+        "Host":"localhost",
+        "User-Agent":"curl/7.38.0",
+        "Accept":"*/*",
+        "User-Agent":"My sweet little browser",
+        "Cookie": "PHPSESSID=rAAAAAAA2t5uvjq435r4q7ib3vtdjq120"
+      },
+      "uri":"/?key=value&key=other_value",
+      "method":"GET"
+    },
+    "server":{
+      "ip":"200.249.12.31",
+      "port":80
+    },
+    "rules":[
+      "SecRuleEngine On",
+      "SecDebugLog \/tmp\/modsec_debug.log",
+      "SecRule REQUEST_HEADERS:User-Agent \"^(.*)$\" \"id:'900018',phase:1,t:none,t:sha1,t:hexEncode,setsid:%{REQUEST_COOKIES:PHPSESSID}%,nolog,pass\"",
+      "SecRule REQUEST_HEADERS \".*\" \"id:'900021',phase:1,setvar:SESSION.score=+10\"",
+      "SecRule REQUEST_HEADERS:User-Agent \"^(.*)$\" \"id:'900068',phase:1,t:none,t:sha1,t:hexEncode,setsid:%{REQUEST_COOKIES:PHPSESSID}2,nolog,pass\"",
+      "SecRule REQUEST_HEADERS \".*\" \"id:'900022',phase:1,setvar:SESSION.score=+5\"",
+      "SecRule SESSIONID \".*\" \"id:1239,phase:1,log,pass\""
+    ]
+  },
+  {
+    "enabled":1,
+    "version_min":300000,
+    "title":"Testing SESSIONID variable (2/2)",
+    "expected":{
+      "debug_log": "Target value: \"whee\""
+    },
+    "client":{
+      "ip":"200.249.12.31",
+      "port":123
+    },
+    "request":{
+      "headers":{
+        "Host":"localhost",
+        "User-Agent":"curl/7.38.0",
+        "Accept":"*/*",
+        "User-Agent":"My sweet little browser",
+        "Cookie": "PHPSESSID=whee"
+      },
+      "uri":"/?key=value&key=other_value",
+      "method":"GET"
+    },
+    "server":{
+      "ip":"200.249.12.31",
+      "port":80
+    },
+    "rules":[
+      "SecRuleEngine On",
+      "SecDebugLog \/tmp\/modsec_debug.log",
+      "SecRule REQUEST_HEADERS:User-Agent \"^(.*)$\" \"id:'900018',phase:1,t:none,t:sha1,t:hexEncode,setsid:%{REQUEST_COOKIES:PHPSESSID}%,nolog,pass\"",
+      "SecRule REQUEST_HEADERS \".*\" \"id:'900021',phase:1,setvar:SESSION.score=+10\"",
+      "SecRule SESSIONID \".*\" \"id:1239,phase:1,log,pass\""
+    ]
+  }
+]
\ No newline at end of file