diff --git a/src/Ratchet/WebSocket/Version/RFC6455.php b/src/Ratchet/WebSocket/Version/RFC6455.php
index 23e166c..fe37acb 100644
--- a/src/Ratchet/WebSocket/Version/RFC6455.php
+++ b/src/Ratchet/WebSocket/Version/RFC6455.php
@@ -154,6 +154,8 @@ class RFC6455 implements VersionInterface {
                             return $from->close($frame::CLOSE_BAD_PAYLOAD);
                         }
 
+                        $frame->unMaskPayload();
+
                         return $from->close($frame);
                     break;
                     case $frame::OP_PING: