diff --git a/src/core/thread/mesh_forwarder.cpp b/src/core/thread/mesh_forwarder.cpp
index 5f90b3235..ce351401c 100644
--- a/src/core/thread/mesh_forwarder.cpp
+++ b/src/core/thread/mesh_forwarder.cpp
@@ -1302,9 +1302,6 @@ void MeshForwarder::HandleFragment(uint8_t *aFrame, uint8_t aFrameLength,
         headerLength = mLowpan.Decompress(*message, aMacSource, aMacDest, aFrame, aFrameLength, datagramLength);
         VerifyOrExit(headerLength > 0, error = kThreadError_NoBufs);
 
-        // Security Check
-        VerifyOrExit(mNetif.GetIp6Filter().Accept(*message), error = kThreadError_Drop);
-
         aFrame += headerLength;
         aFrameLength -= headerLength;
 
@@ -1314,6 +1311,13 @@ void MeshForwarder::HandleFragment(uint8_t *aFrame, uint8_t aFrameLength,
         message->SetDatagramTag(datagramTag);
         message->SetTimeout(kReassemblyTimeout);
 
+        // copy Fragment
+        message->Write(message->GetOffset(), aFrameLength, aFrame);
+        message->MoveOffset(aFrameLength);
+
+        // Security Check
+        VerifyOrExit(mNetif.GetIp6Filter().Accept(*message), error = kThreadError_Drop);
+
         mReassemblyList.Enqueue(*message);
 
         if (!mReassemblyTimer.IsRunning())
@@ -1339,14 +1343,12 @@ void MeshForwarder::HandleFragment(uint8_t *aFrame, uint8_t aFrameLength,
         }
 
         VerifyOrExit(message != NULL, error = kThreadError_Drop);
+
+        // copy Fragment
+        message->Write(message->GetOffset(), aFrameLength, aFrame);
+        message->MoveOffset(aFrameLength);
     }
 
-    assert(message != NULL);
-
-    // copy Fragment
-    message->Write(message->GetOffset(), aFrameLength, aFrame);
-    message->MoveOffset(aFrameLength);
-
 exit:
 
     if (error == kThreadError_None)
@@ -1412,9 +1414,6 @@ void MeshForwarder::HandleLowpanHC(uint8_t *aFrame, uint8_t aFrameLength,
     headerLength = mLowpan.Decompress(*message, aMacSource, aMacDest, aFrame, aFrameLength, 0);
     VerifyOrExit(headerLength > 0, error = kThreadError_Drop);
 
-    // Security Check
-    VerifyOrExit(mNetif.GetIp6Filter().Accept(*message), error = kThreadError_Drop);
-
     aFrame += headerLength;
     aFrameLength -= headerLength;
 
@@ -1425,6 +1424,9 @@ void MeshForwarder::HandleLowpanHC(uint8_t *aFrame, uint8_t aFrameLength,
 
     message->Write(message->GetOffset(), aFrameLength, aFrame);
 
+    // Security Check
+    VerifyOrExit(mNetif.GetIp6Filter().Accept(*message), error = kThreadError_Drop);
+
 exit:
 
     if (error == kThreadError_None)