Firefox 3.51 New Vulnerability and POC exploit
A buffer overflow vulnerability has been discovered and FF users should look for a patch soon. A proof-of-concept exploit has been developed and so far no known attacks in the wild have been documented. Some mitigation techniques include: Noscript, AV protection, and safe practices
Mozilla Firefox 3.5 Unicode Data Remote Stack Buffer Overflow Vulnerability
QUOTE: Various analysts and sites have recently confirmed a vulnerability is present in FireFox 3.5.1 that has had exploit PoC released. When exploited, the vulnerability can lead to system compromise or induce a DOS. No Patch is available.