diff --git a/RELEASE_NOTES b/RELEASE_NOTES
index 1305871d9..6c0f60b58 100644
--- a/RELEASE_NOTES
+++ b/RELEASE_NOTES
@@ -72,6 +72,7 @@ Bugs fixed
 - Bug 2436 - SendBlockAckAfterAmpdu is called even if the A-MPDU frame is not addressed to the station
 - Bug 2438 - Routing protocols should stop processing packets coming from a non-forwarding interface
 - Bug 2439 - SixLowPan Compression kind need to be casted to int in the Print function
+- Bug 2440 - SocketIpTosTag might be added twice if a packet is sent multiple times
 
 Known issues
 ------------
diff --git a/src/internet/model/udp-socket-impl.cc b/src/internet/model/udp-socket-impl.cc
index e8dce187c..d66ab27ed 100644
--- a/src/internet/model/udp-socket-impl.cc
+++ b/src/internet/model/udp-socket-impl.cc
@@ -489,7 +489,8 @@ UdpSocketImpl::DoSendTo (Ptr<Packet> p, Ipv4Address dest, uint16_t port)
     {
       SocketIpTosTag ipTosTag;
       ipTosTag.SetTos (GetIpTos ());
-      p->AddPacketTag (ipTosTag);
+      // This packet may already have a SocketIpTosTag (see BUG 2440)
+      p->ReplacePacketTag (ipTosTag);
     }
 
   Ptr<Ipv4> ipv4 = m_node->GetObject<Ipv4> ();