Mozilla Firefox 3.6a1, 3.5.3, 3.5.2, and earlier 3.5.x versions, and 3.0.14 and earlier 2.x and 3.x versions, on Linux uses a predictable /tmp pathname for files selected from the Downloads window, which allows local users to replace an arbitrary downloaded file by placing a file in a /tmp location before the download occurs, related to the Download Manager component. NOTE: some of these details are obtained from third party information.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A9641
https://bugzilla.mozilla.org/show_bug.cgi?id=514823
http://www.vupen.com/english/advisories/2010/0650
http://www.vupen.com/english/advisories/2009/3334
http://www.redhat.com/support/errata/RHSA-2010-0154.html
http://www.redhat.com/support/errata/RHSA-2010-0153.html
http://www.mozilla.org/security/announce/2009/mfsa2009-53.html
http://securitytube.net/Zero-Day-Demos-%28Firefox-Vulnerability-Discovered%29-video.aspx