diff --git a/source/libs/transport/src/transCli.c b/source/libs/transport/src/transCli.c
index d5739cde58..8f83b1bde2 100644
--- a/source/libs/transport/src/transCli.c
+++ b/source/libs/transport/src/transCli.c
@@ -713,10 +713,22 @@ static SCliConn* getConnFromPool2(SCliThrd* pThrd, char* key, SCliMsg** pMsg) {
       }
 
       STaskArg* arg = taosMemoryMalloc(sizeof(STaskArg));
+      if (arg == NULL) {
+        doNotifyApp(*pMsg, pThrd, TSDB_CODE_OUT_OF_MEMORY);
+        *pMsg = NULL;
+        return NULL;
+      }
       arg->param1 = *pMsg;
       arg->param2 = pThrd;
 
-      (*pMsg)->ctx->task = transDQSched(pThrd->waitConnQueue, doFreeTimeoutMsg, arg, pTransInst->timeToGetConn);
+      SDelayTask* task = transDQSched(pThrd->waitConnQueue, doFreeTimeoutMsg, arg, pTransInst->timeToGetConn);
+      if (task == NULL) {
+        taosMemoryFree(arg);
+        doNotifyApp(*pMsg, pThrd, TSDB_CODE_OUT_OF_MEMORY);
+        *pMsg = NULL;
+        return NULL;
+      }
+      (*pMsg)->ctx->task = task;
       tGTrace("%s msg %s delay to send, wait for avaiable connect", pTransInst->label, TMSG_INFO((*pMsg)->msg.msgType));
       QUEUE_PUSH(&(list)->msgQ, &(*pMsg)->q);
       *pMsg = NULL;
@@ -724,9 +736,23 @@ static SCliConn* getConnFromPool2(SCliThrd* pThrd, char* key, SCliMsg** pMsg) {
       // send msg in delay queue
       if (!(QUEUE_IS_EMPTY(&(list)->msgQ))) {
         STaskArg* arg = taosMemoryMalloc(sizeof(STaskArg));
+        if (arg == NULL) {
+          doNotifyApp(*pMsg, pThrd, TSDB_CODE_OUT_OF_MEMORY);
+          *pMsg = NULL;
+          return NULL;
+        }
         arg->param1 = *pMsg;
         arg->param2 = pThrd;
-        (*pMsg)->ctx->task = transDQSched(pThrd->waitConnQueue, doFreeTimeoutMsg, arg, pTransInst->timeToGetConn);
+        SDelayTask* task = transDQSched(pThrd->waitConnQueue, doFreeTimeoutMsg, arg, pTransInst->timeToGetConn);
+
+        if (task == NULL) {
+          taosMemoryFree(arg);
+          doNotifyApp(*pMsg, pThrd, TSDB_CODE_OUT_OF_MEMORY);
+          *pMsg = NULL;
+          return NULL;
+        }
+
+        (*pMsg)->ctx->task = task;
         tGTrace("%s msg %s delay to send, wait for avaiable connect", pTransInst->label,
                 TMSG_INFO((*pMsg)->msg.msgType));
 
@@ -766,7 +792,11 @@ static void addConnToPool(void* pool, SCliConn* conn) {
   if (conn->status == ConnInPool) {
     return;
   }
-  allocConnRef(conn, true);
+  int32_t code = allocConnRef(conn, true);
+  if (code != 0) {
+    cliDestroyConn(conn, true);
+    return;
+  }
 
   SCliThrd* thrd = conn->hostThrd;
   if (conn->timer != NULL) {
@@ -811,6 +841,7 @@ static void addConnToPool(void* pool, SCliConn* conn) {
 
   if (conn->list->size >= 10) {
     STaskArg* arg = taosMemoryCalloc(1, sizeof(STaskArg));
+    if (arg == NULL) return;
     arg->param1 = conn;
     arg->param2 = thrd;
 
@@ -826,9 +857,12 @@ static int32_t allocConnRef(SCliConn* conn, bool update) {
   }
 
   SExHandle* exh = taosMemoryCalloc(1, sizeof(SExHandle));
+  if (exh == NULL) {
+    return TSDB_CODE_OUT_OF_MEMORY;
+  }
+
   exh->refId = transAddExHandle(transGetRefMgt(), exh);
-  SExHandle* self = transAcquireExHandle(transGetRefMgt(), exh->refId);
-  if (self != exh) {
+  if (exh->refId < 0) {
     taosMemoryFree(exh);
     return TSDB_CODE_REF_INVALID_ID;
   }
@@ -838,8 +872,14 @@ static int32_t allocConnRef(SCliConn* conn, bool update) {
   exh->handle = conn;
   exh->pThrd = conn->hostThrd;
 
+  SExHandle* self = transAcquireExHandle(transGetRefMgt(), exh->refId);
+  if (self != exh) {
+    taosMemoryFree(exh);
+    return TSDB_CODE_REF_INVALID_ID;
+  }
+
   conn->refId = exh->refId;
-  if (conn->refId == -1) {
+  if (conn->refId < 0) {
     taosMemoryFree(exh);
   }
   return 0;
diff --git a/source/libs/transport/src/transComm.c b/source/libs/transport/src/transComm.c
index 8a64b7d808..aa6b377423 100644
--- a/source/libs/transport/src/transComm.c
+++ b/source/libs/transport/src/transComm.c
@@ -637,6 +637,10 @@ void transDQCancel(SDelayQueue* queue, SDelayTask* task) {
 SDelayTask* transDQSched(SDelayQueue* queue, void (*func)(void* arg), void* arg, uint64_t timeoutMs) {
   uint64_t    now = taosGetTimestampMs();
   SDelayTask* task = taosMemoryCalloc(1, sizeof(SDelayTask));
+  if (task == NULL) {
+    return NULL;
+  }
+
   task->func = func;
   task->arg = arg;
   task->execTime = now + timeoutMs;