CVE-2018-5152: Canonical Ubuntu Linux

Medium severity, CVSS 6.5. EPSS: 1.6% chance of exploitation in the next 30 days.

WebExtensions with the appropriate permissions can attach content scripts to Mozilla sites such as accounts.firefox.com and listen to network traffic to the site through the "webRequest" API. For example, this allows for the interception of username and an encrypted password during login to Firefox Accounts. This issue does not expose synchronization traffic directly and is limited to the process of user login to the website and the data displayed to the user once logged in. 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.