CVE 2007-3285
Mozilla Firefox before 2.0.0.5, when run on Windows, allows remote attackers to bypass file type checks and possibly execute programs via a (1) file:/// or (2) resource: URI with a dangerous extension, followed by a NULL byte (%00) and a safer extension, which causes Firefox to treat the requested file differently than Windows would.
See the 
CVE page on Mitre.org
for more details.
