CVE-2018-5092: Canonical Ubuntu Linux

Critical severity, CVSS 9.8. EPSS: 1.8% chance of exploitation in the next 30 days.

A use-after-free vulnerability can occur when the thread for a Web Worker is freed from memory prematurely instead of from memory in the main thread while cancelling fetch operations. This vulnerability affects Firefox < 58.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 17.10 only
• Mozilla Firefox: up to and including 57.0.4

Published 2018-06-11. Last modified 2026-06-17.