diff --git a/NetworkPkg/Include/Library/NetLib.h b/NetworkPkg/Include/Library/NetLib.h
index e8108b79db..34e89dad44 100644
--- a/NetworkPkg/Include/Library/NetLib.h
+++ b/NetworkPkg/Include/Library/NetLib.h
@@ -2081,7 +2081,8 @@ NetbufQueAppend (
   @param[out]  Dest            The destination of the data to copy to.
 
   @return       The length of the actual copied data, or 0 if the offset
-                specified exceeds the total size of net buffer queue.
+                specified exceeds the total size of net buffer queue, or
+                a NetBuf pointer is NULL.
 
 **/
 UINT32
diff --git a/NetworkPkg/Library/DxeNetLib/NetBuffer.c b/NetworkPkg/Library/DxeNetLib/NetBuffer.c
index 4721fbd270..3827f5afcf 100644
--- a/NetworkPkg/Library/DxeNetLib/NetBuffer.c
+++ b/NetworkPkg/Library/DxeNetLib/NetBuffer.c
@@ -1430,7 +1430,8 @@ NetbufQueRemove (
   @param[out]  Dest            The destination of the data to copy to.
 
   @return       The length of the actual copied data, or 0 if the offset
-                specified exceeds the total size of net buffer queue.
+                specified exceeds the total size of net buffer queue, or
+                a NetBuf pointer is NULL.
 
 **/
 UINT32
@@ -1476,7 +1477,10 @@ NetbufQueCopy (
     Cur += Nbuf->TotalSize;
   }
 
-  ASSERT (Nbuf != NULL);
+  if (Nbuf == NULL) {
+    ASSERT (FALSE);
+    return 0;
+  }
 
   //
   // Copy the data in the first buffer.