CVE-2016-5257: Mozilla Firefox

Critical severity, CVSS 9.8. EPSS: 4.2% chance of exploitation in the next 30 days.

Multiple unspecified vulnerabilities in the browser engine in Mozilla Firefox before 49.0, Firefox ESR 45.x before 45.4 and Thunderbird < 45.4 allow remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unknown vectors.

Affected products

• Mozilla Firefox: up to and including 48.0.2; version 45.1.0 only; version 45.1.1 only; version 45.2.0 only; version 45.3.0 only

Published 2016-09-22. Last modified 2026-06-17.