layout/base/nsCSSFrameConstructor.cpp in the browser engine in Mozilla Firefox 3.0.x before 3.0.15 does not properly handle first-letter frames, which allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unspecified vectors.
sunsolve.sun.com/search/document.do?assetkey=1-26-272909-1
www.mozilla.org/security/announce/2009/mfsa2009-64.html
www.vupen.com/english/advisories/2009/3334
bugzilla.mozilla.org/show_bug.cgi?id=514960
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11219
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A5581