CVE 2005-0142
Firefox 0.9, Thunderbird 0.6 and other versions before 0.9, and Mozilla 1.7 before 1.7.5 save temporary files with world-readable permissions, which allows local users to read certain web content or attachments that belong to other users, e.g. content that is managed by helper applications such as PDF.
See the 
CVE page on Mitre.org
for more details.
