CVE-2019-11759

CVE-2019-11759 is a critical buffer overflow vulnerability affecting Mozilla Firefox, Thunderbird, and Firefox ESR versions prior to 70, 68.2, and 68.2 respectively. An attacker could exploit this by causing 4 bytes of HMAC output to be written past a stack buffer, potentially leading to arbitrary code execution or a denial-of-service crash. With a CVSS score of 8.8 (High), this vulnerability is easily exploitable over a network with user interaction, enabling high impact to confidentiality, integrity, and availability. While no public exploits (Metasploit, Nuclei, ExploitDB) or active exploitation (KEV) have been identified, and community discussion is minimal, the potential for severe impact warrants prompt patching.