Google Chrome before 15.0.874.120 does not properly implement the MKV and Vorbis media handlers, which allows remote attackers to cause a denial of service (out-of-bounds read) via unspecified vectors.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A14267
http://secunia.com/advisories/49089
http://secunia.com/advisories/46933
http://googlechromereleases.blogspot.com/2011/11/stable-channel-update.html