diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 70b07f8c..7a6a6b54 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -1,6 +1,10 @@
 # Changelog
 All changes to this project will be documented in this file.
 
+## [9.1.1] - 2020-03-26
+
+(websocket) fix data race accessing _socket object without mutex protection when calling wakeUpFromPoll in WebSocketTransport.cpp
+
 ## [9.1.0] - 2020-03-26
 
 (ixcobra) add explicit event types for handshake, authentication and subscription failure, and handle those by exiting in ws_cobra_subcribe and friends
diff --git a/ixwebsocket/IXWebSocketTransport.cpp b/ixwebsocket/IXWebSocketTransport.cpp
index 946d3878..df80cd58 100644
--- a/ixwebsocket/IXWebSocketTransport.cpp
+++ b/ixwebsocket/IXWebSocketTransport.cpp
@@ -625,7 +625,7 @@ namespace ix
                     // send back the CLOSE frame
                     sendCloseFrame(code, reason);
 
-                    _socket->wakeUpFromPoll(Socket::kCloseRequest);
+                    wakeUpFromPoll(Socket::kCloseRequest);
 
                     bool remote = true;
                     closeSocketAndSwitchToClosedState(code, reason, _rxbuf.size(), remote);
@@ -845,7 +845,7 @@ namespace ix
         // Request to flush the send buffer on the background thread if it isn't empty
         if (!isSendBufferEmpty())
         {
-            _socket->wakeUpFromPoll(Socket::kSendRequest);
+            wakeUpFromPoll(Socket::kSendRequest);
 
             // FIXME: we should have a timeout when sending large messages: see #131
             if (_blockingSend && !flushSendBuffer())
@@ -1063,6 +1063,12 @@ namespace ix
         _socket->close();
     }
 
+    bool WebSocketTransport::wakeUpFromPoll(uint64_t wakeUpCode)
+    {
+        std::lock_guard<std::mutex> lock(_socketMutex);
+        return _socket->wakeUpFromPoll(wakeUpCode);
+    }
+
     void WebSocketTransport::closeSocketAndSwitchToClosedState(uint16_t code,
                                                                const std::string& reason,
                                                                size_t closeWireSize,
@@ -1110,8 +1116,9 @@ namespace ix
         setReadyState(ReadyState::CLOSING);
 
         sendCloseFrame(code, reason);
+
         // wake up the poll, but do not close yet
-        _socket->wakeUpFromPoll(Socket::kSendRequest);
+        wakeUpFromPoll(Socket::kSendRequest);
     }
 
     size_t WebSocketTransport::bufferedAmount() const
diff --git a/ixwebsocket/IXWebSocketTransport.h b/ixwebsocket/IXWebSocketTransport.h
index e3c5df20..91ad564a 100644
--- a/ixwebsocket/IXWebSocketTransport.h
+++ b/ixwebsocket/IXWebSocketTransport.h
@@ -229,6 +229,8 @@ namespace ix
                                                size_t closeWireSize,
                                                bool remote);
 
+        bool wakeUpFromPoll(uint64_t wakeUpCode);
+
         bool flushSendBuffer();
         bool sendOnSocket();
         bool receiveFromSocket();
diff --git a/ixwebsocket/IXWebSocketVersion.h b/ixwebsocket/IXWebSocketVersion.h
index d4573a2b..4557837d 100644
--- a/ixwebsocket/IXWebSocketVersion.h
+++ b/ixwebsocket/IXWebSocketVersion.h
@@ -6,4 +6,4 @@
 
 #pragma once
 
-#define IX_WEBSOCKET_VERSION "9.1.0"
+#define IX_WEBSOCKET_VERSION "9.1.1"