remote system compromise in cvs

CVS (Concurrent Versions System) is a version control system which helps to manage concurrent editing of files by various authors. Stefan Esser of e-matters reported a “double free” bug in CVS server code for handling directory requests. This free() call allows an attacker with CVS read access to compromise a CVS server. Additionally two features (‘Update-prog’ and ‘Checkin-prog’) were disabled to stop clients with write access to execute arbitrary code on the server. These features may be configurable at run-time in future releases of CVS server.