CVE-2016-5258: Mozilla Firefox

High severity, CVSS 8.8. EPSS: 3.3% chance of exploitation in the next 30 days.

Use-after-free vulnerability in the WebRTC socket thread in Mozilla Firefox before 48.0 and Firefox ESR 45.x before 45.3 allows remote attackers to execute arbitrary code by leveraging incorrect free operations on DTLS objects during the shutdown of a WebRTC session.

Affected products

• Mozilla Firefox: up to and including 47.0.1; version 45.1.0 only; version 45.1.1 only; version 45.2.0 only; version 45.3.0 only
• Oracle Linux: version 5.0 only; version 6 only; version 7 only

Published 2016-08-05. Last modified 2026-06-17.