Firefox before 1.0.1 and Mozilla Suite before 1.7.6 use a predictable filename for the plugin temporary directory, which allows local users to delete arbitrary files of other users via a symlink attack on the plugtmp directory.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10954
http://www.securityfocus.com/bid/12659
http://www.redhat.com/support/errata/RHSA-2005-384.html
http://www.redhat.com/support/errata/RHSA-2005-176.html
http://www.mozilla.org/security/announce/mfsa2005-28.html