CVE-2018-5166: Canonical Ubuntu Linux

High severity, CVSS 7.5. EPSS: 2.4% chance of exploitation in the next 30 days.

WebExtensions can use request redirection and a "filterReponseData" filter to bypass host permission settings to redirect network traffic and access content from a host for which they do not have explicit user permission. This vulnerability affects Firefox < 60.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 17.10 only; version 18.04 only
• Mozilla Firefox: before 60.0 (fixed in 60.0)

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