diff --git a/simgear/compatibility/sstream b/simgear/compatibility/sstream
index 2eb05195..d531aac3 100644
--- a/simgear/compatibility/sstream
+++ b/simgear/compatibility/sstream
@@ -10,6 +10,7 @@ namespace std {
 
    class ostringstream : public ostrstream {
    public:
+      ~ostringstream() { delete ostrstream::str(); }
       std::string str() { return string(ostrstream::str()) + '\0'; }
    };