Mozilla Firefox before 5.0 does not properly enforce the whitelist for the xpinstall functionality, which allows remote attackers to trigger an installation dialog for a (1) add-on or (2) theme via unspecified vectors.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A14278
https://bugzilla.mozilla.org/show_bug.cgi?id=645699
http://www.mozilla.org/security/announce/2011/mfsa2011-28.html
http://lists.opensuse.org/opensuse-security-announce/2011-07/msg00001.html