Security watchers warn that an unpatched vulnerability in RealPlayer poses a severe risk.

A flaw in RealPlayer 11 build 6.0.14.748 might be used to inject hostile code onto Windows boxes running the software, security notification firm Secunia warns. Other versions of the media player software may also be vulnerable.

The vulnerability stems from a stack overflow bug in RealPlayer 11 discovered by Russian security firm Gleg. The firm discovered the flaw during an audit of RealPlayer's source code. Gleg has not released technical details of the flaw, pending the release of a patch, but it has posted a flash demo of the vulnerability here.

Security clearing house US CERT issued an advisory warning of heightened risk stemming from the flaw following the publication of a proof of concept exploit. RealNetworks is investigating the flaw, SC Magazine adds. The developer criticised Gleg for posting the proof of concept exploit without giving it a chance to fix the bug first.

Users of the popular media player are advised to be careful about opening untrusted media files, particularly those found on untrusted websites, to minimise the risk of finding their systems owned as a result of the flaw. ®