CVE-2018-18497: Canonical Ubuntu Linux

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

Limitations on the URIs allowed to WebExtensions by the browser.windows.create API can be bypassed when a pipe in the URL field is used within the extension to load multiple pages as a single argument. This could allow a malicious WebExtension to open privileged about: or file: locations. This vulnerability affects Firefox < 64.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 18.04 only; version 18.10 only
• Mozilla Firefox: before 64.0 (fixed in 64.0)

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