CVE-2016-5276: Mozilla Firefox

Critical severity, CVSS 9.8. EPSS: 4% chance of exploitation in the next 30 days.

Use-after-free vulnerability in the mozilla::a11y::DocAccessible::ProcessInvalidationList function in Mozilla Firefox before 49.0, Firefox ESR 45.x before 45.4, and Thunderbird < 45.4 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) via an aria-owns attribute.

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.