firefox is vulnerable to arbitrary code execution. The vulnerability exists as two use-after-free flaws were found in the Firefox mObserverList and mChannel objects. Malicious content could use these flaws to execute arbitrary code with the privileges of the user running Firefox.
downloads.avaya.com/css/P8/documents/100144158
securityreason.com/securityalert/8326
securityreason.com/securityalert/8331
securityreason.com/securityalert/8340
www.debian.org/security/2011/dsa-2227
www.debian.org/security/2011/dsa-2228
www.debian.org/security/2011/dsa-2235
www.mandriva.com/security/advisories?name=MDVSA-2011:079
www.mozilla.org/security/announce/2011/mfsa2011-13.html
www.mozilla.org/security/known-vulnerabilities/firefox36.html#firefox3.6.17
access.redhat.com/errata/RHSA-2011:0471
access.redhat.com/security/updates/classification/#critical
bugzilla.mozilla.org/show_bug.cgi?id=634986
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A14142