CVE 2008-5510
The CSS parser in Mozilla Firefox 3.x before 3.0.5 and 2.x before 2.0.0.19, Thunderbird 2.x before 2.0.0.19, and SeaMonkey 1.x before 1.1.14 ignores the '\0' escaped null character, which might allow remote attackers to bypass protection mechanisms such as sanitization routines.
See the 
CVE page on Mitre.org
for more details.
