CVE-2018-12398: Canonical Ubuntu Linux

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

By using the reflected URL in some special resource URIs, such as chrome:, it is possible to inject stylesheets and bypass Content Security Policy (CSP). This vulnerability affects Firefox < 63.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 18.04 only; version 18.10 only
• Mozilla Firefox: before 63.0 (fixed in 63.0)

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