The nsIScriptableUnescapeHTML.parseFragment method in the ParanoidFragmentSink protection mechanism in Mozilla Firefox before 3.5.17 and 3.6.x before 3.6.14, Thunderbird before 3.1.8, and SeaMonkey before 2.0.12 does not properly sanitize HTML in a chrome document, which makes it easier for remote attackers to execute arbitrary JavaScript with chrome privileges via a javascript: URI in input to an extension, as demonstrated by a javascript:alert sequence in (1) the HREF attribute of an A element or (2) the ACTION attribute of a FORM element.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12532
https://bugzilla.mozilla.org/show_bug.cgi?id=562547
http://www.securityfocus.com/archive/1/510883/100/0/threaded
http://www.mozilla.org/security/announce/2011/mfsa2011-08.html
http://www.mandriva.com/security/advisories?name=MDVSA-2011:042
http://www.mandriva.com/security/advisories?name=MDVSA-2011:041
http://wizzrss.blat.co.za/2009/11/17/so-much-for-nsiscriptableunescapehtmlparsefragment/