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.
http://www.vupen.com/english/advisories/2011/1241
http://www.ubuntu.com/usn/usn-1104-1/
http://www.securityfocus.com/bid/47151
http://www.mandriva.com/security/advisories?name=MDVSA-2011:114
http://www.mandriva.com/security/advisories?name=MDVSA-2011:112
http://www.mandriva.com/security/advisories?name=MDVSA-2011:089
http://www.mandriva.com/security/advisories?name=MDVSA-2011:062
http://www.mandriva.com/security/advisories?name=MDVSA-2011:061