CVE-2018-12367: Canonical Ubuntu Linux

Medium severity, CVSS 4.3. EPSS: 2% chance of exploitation in the next 30 days.

In the previous mitigations for Spectre, the resolution or precision of various methods was reduced to counteract the ability to measure precise time intervals. In that work PerformanceNavigationTiming was not adjusted but it was found that it could be used as a precision timer. This vulnerability affects Thunderbird < 60, Firefox ESR < 60.1, and Firefox < 61.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 17.10 only; version 18.04 only
• Debian Debian Linux: version 8.0 only; version 9.0 only
• Mozilla Firefox: before 60.1.0 (fixed in 60.1.0); before 61.0 (fixed in 61.0)
• Mozilla Thunderbird: before 60.0 (fixed in 60.0)

Published 2018-10-18. Last modified 2026-06-17.