diff --git a/CHANGES_NEXT_RELEASE b/CHANGES_NEXT_RELEASE
index 68d1efb13a..d37a866524 100644
--- a/CHANGES_NEXT_RELEASE
+++ b/CHANGES_NEXT_RELEASE
@@ -1,4 +1,6 @@
+- Fix: memory leak in POST /v2/op/notify operation (#4261)
 - Fix: service path levels with 0 length should not be allowed (#4495)
 - Fix: changed the default value of `-dbTimeout` to 0 to resolve conflict with `-dbURI` (#4496) 
 - Fix: wrong INFO startup log showing ORION_MONGO_TIMEOUT, ORION_IN_REQ_PAYLOAD_MAX_SIZE and ORION_OUT_REQ_MSG_MAX_SIZE env var values (#4496)
 - Fix: return 400 Bad Request when subject.entities exists but it is an empty array (#4499)
+
diff --git a/src/lib/jsonParseV2/parseNotification.cpp b/src/lib/jsonParseV2/parseNotification.cpp
index dd975f2e2f..fa2e441c0b 100644
--- a/src/lib/jsonParseV2/parseNotification.cpp
+++ b/src/lib/jsonParseV2/parseNotification.cpp
@@ -116,6 +116,8 @@ static bool parseNotificationData
 
     if (parseContextElementResponse(ciP, iter2, cerP, oeP) == false)
     {
+      //delete the allocated memory and return false
+      delete cerP;
       return false;
     }
   }
diff --git a/test/functionalTest/cases/0000_statistics_operation/statistics_with_counters.test b/test/functionalTest/cases/0000_statistics_operation/statistics_with_counters.test
index 26f899f85f..7205170f25 100644
--- a/test/functionalTest/cases/0000_statistics_operation/statistics_with_counters.test
+++ b/test/functionalTest/cases/0000_statistics_operation/statistics_with_counters.test
@@ -143,9 +143,7 @@ payload='{
     }
   ]
 }'
-# FIXME #4261. Once the issue gets solved, this line should be uncommented
-# The REGEXPECT part would need a little adapation after that
-#orionCurl --url /v2/op/notify -X POST   --payload "$payload"  > /dev/null
+orionCurl --url /v2/op/notify -X POST   --payload "$payload"  > /dev/null
 
 
 payload='{
@@ -263,7 +261,7 @@ Content-Length: REGEX(\d+)
         "deprecatedFeatures": {
             "ngsiv1Requests": 7
         },
-        "jsonRequests": 16,
+        "jsonRequests": 17,
         "noPayloadRequests": 42,
         "requests": {
             "/admin/log": {
@@ -317,6 +315,9 @@ Content-Length: REGEX(\d+)
                 "POST": 1,
                 "PUT": 1
             },
+            "/v2/op/notify": {
+                "POST": 1
+            },
             "/v2/op/query": {
                 "OPTIONS": 1,
                 "POST": 1
@@ -324,7 +325,7 @@ Content-Length: REGEX(\d+)
             "/v2/op/update": {
                 "OPTIONS": 1,
                 "POST": 1
-            },
+            },       
             "/v2/registrations": {
                 "GET": 1,
                 "OPTIONS": 1,