diff --git a/RELEASE_NOTES b/RELEASE_NOTES
index 7d7b76b30..a3dcf7dfa 100644
--- a/RELEASE_NOTES
+++ b/RELEASE_NOTES
@@ -116,6 +116,7 @@ Bugs fixed
 - Bug 2761 - Packet has no Traffic ID for CTS frames when A-MPDU is used
 - Bug 2762 - BindToNetDevice behaviour is not coherent with Linux
 - Bug 2763 - wifi management packets in the PCAPs are all marked as wrong by Wireshark
+- Bug 2769 - Set ssthresh correctly upon RTO
 
 Known issues
 ------------
diff --git a/src/internet/model/tcp-socket-base.cc b/src/internet/model/tcp-socket-base.cc
index 1a5faa1bb..275b03297 100644
--- a/src/internet/model/tcp-socket-base.cc
+++ b/src/internet/model/tcp-socket-base.cc
@@ -3152,6 +3152,8 @@ TcpSocketBase::ReTxTimeout ()
       return;
     }
 
+  uint32_t inFlightBeforeRto = BytesInFlight();  
+
   // From RFC 6675, Section 5.1
   // [RFC2018] suggests that a TCP sender SHOULD expunge the SACK
   // information gathered from a receiver upon a retransmission timeout
@@ -3204,7 +3206,7 @@ TcpSocketBase::ReTxTimeout ()
   // retransmission timer, decrease ssThresh
   if (m_tcb->m_congState != TcpSocketState::CA_LOSS || !m_txBuffer->IsHeadRetransmitted ())
     {
-      m_tcb->m_ssThresh = m_congestionControl->GetSsThresh (m_tcb, BytesInFlight ());
+      m_tcb->m_ssThresh = m_congestionControl->GetSsThresh (m_tcb, inFlightBeforeRto);
     }
 
   // Cwnd set to 1 MSS