SeaMonkey is vulnerable to erroneous stylesheet caching. The CSSLoaderImpl::DoSheetComplete function in layout/style/nsCSSLoader.cpp changes the case of certain strings in a stylesheet before adding this stylesheet to the XUL cache, which might allow remote attackers to modify the browser’s font and other CSS attributes, and potentially disrupt rendering of a web page, by forcing the browser to perform this erroneous stylesheet caching.
www.mozilla.org/security/announce/2010/mfsa2010-14.html
www.redhat.com/security/updates/classification/#critical
www.securityfocus.com/bid/38918
www.vupen.com/english/advisories/2010/0692
access.redhat.com/errata/RHSA-2010:0113
bugzilla.mozilla.org/show_bug.cgi?id=535806
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11391
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A8431