CVE-2012-3964

CVE-2012-3964 is a critical use-after-free vulnerability in the gfxTextRun::GetUserData function affecting Mozilla Firefox, Thunderbird, and SeaMonkey versions prior to 15.0 (and respective ESR versions). This flaw allows remote attackers to execute arbitrary code or cause a denial of service through heap memory corruption. With a CVSS score of 10.0, it presents a severe risk due to its network-based attack vector, low complexity, and lack of authentication required, leading to complete confidentiality, integrity, and availability compromise. While the vulnerability is severe, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.