diff --git a/libcef/stream_impl.cc b/libcef/stream_impl.cc
index fadae6a86..df8898a22 100644
--- a/libcef/stream_impl.cc
+++ b/libcef/stream_impl.cc
@@ -299,7 +299,7 @@ int CefBytesWriter::Flush()
 std::string CefBytesWriter::GetDataString()
 {
   Lock();
-  std::string str((char*)data_, datasize_);
+  std::string str((char*)data_, offset_);
   Unlock();
   return str;
 }