CVE-2018-12397: Canonical Ubuntu Linux

High severity, CVSS 7.1. EPSS: 0.4% chance of exploitation in the next 30 days.

A WebExtension can request access to local files without the warning prompt stating that the extension will "Access your data for all websites" being displayed to the user. This allows extensions to run content scripts in local pages without permission warnings when a local file is opened. This vulnerability affects Firefox ESR < 60.3 and Firefox < 63.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 18.04 only; version 18.10 only
• Debian Debian Linux: version 8.0 only; version 9.0 only
• Mozilla Firefox: before 60.3.0 (fixed in 60.3.0); before 63.0 (fixed in 63.0)
• Red Hat Enterprise Linux Desktop: version 6.0 only; version 7.0 only
• Red Hat Enterprise Linux Server: version 6.0 only; version 7.0 only
• Red Hat Enterprise Linux Server Eus: version 7.5 only
• Red Hat Enterprise Linux Workstation: version 6.0 only; version 7.0 only

Published 2019-02-28. Last modified 2026-06-17.