CVE-2018-12403: Canonical Ubuntu Linux

Medium severity, CVSS 5.3. EPSS: 2.1% chance of exploitation in the next 30 days.

If a site is loaded over a HTTPS connection but loads a favicon resource over HTTP, the mixed content warning is not displayed to users. 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.