FFmpeg 0.5.x, as used in MPlayer and other products, allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a malformed VC-1 file.
ffmpeg.mplayerhq.hu/
www.debian.org/security/2011/dsa-2306
www.mandriva.com/security/advisories?name=MDVSA-2011:061
www.mandriva.com/security/advisories?name=MDVSA-2011:062
www.mandriva.com/security/advisories?name=MDVSA-2011:089
www.mandriva.com/security/advisories?name=MDVSA-2011:112
www.mandriva.com/security/advisories?name=MDVSA-2011:114
www.securityfocus.com/bid/47151
www.ubuntu.com/usn/usn-1104-1/
www.vupen.com/english/advisories/2011/1241