firefox is vulnerable to arbitrary code execution. The vulnerability exists as a web page containing malicious content could cause Firefox to crash or, potentially, execute arbitrary code as the user running Firefox.
secunia.com/advisories/34241
secunia.com/advisories/35331
secunia.com/advisories/35415
secunia.com/advisories/35431
secunia.com/advisories/35468
secunia.com/secunia_research/2009-19/
slackware.com/security/viewer.php?l=slackware-security&y=2009&m=slackware-security.372468
sunsolve.sun.com/search/document.do?assetkey=1-66-264308-1
www.debian.org/security/2009/dsa-1820
www.mozilla.org/security/announce/2009/mfsa2009-28.html
www.mozilla.org/security/known-vulnerabilities/firefox30.html#firefox3.0.11
www.redhat.com/security/updates/classification/#critical
www.securityfocus.com/archive/1/504260/100/0/threaded
www.securityfocus.com/bid/35326
www.securityfocus.com/bid/35360
www.securitytracker.com/id?1022386
www.vupen.com/english/advisories/2009/1572
access.redhat.com/errata/RHSA-2009:1095
bugzilla.mozilla.org/show_bug.cgi?id=486269
bugzilla.redhat.com/show_bug.cgi?id=503579
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10628
rhn.redhat.com/errata/RHSA-2009-1095.html
www.redhat.com/archives/fedora-package-announce/2009-June/msg00574.html
www.redhat.com/archives/fedora-package-announce/2009-June/msg00657.html