diff --git a/lib/websocket/driver/stream_reader.rb b/lib/websocket/driver/stream_reader.rb
index d63b2f7..a89c4d2 100644
--- a/lib/websocket/driver/stream_reader.rb
+++ b/lib/websocket/driver/stream_reader.rb
@@ -12,6 +12,7 @@ def initialize
 
       def put(chunk)
         return unless chunk and chunk.bytesize > 0
+        chunk = chunk.dup if chunk.frozen?
         @buffer << chunk.force_encoding(Encoding::BINARY)
       end