CVE-2020-12419: Canonical Ubuntu Linux

High severity, CVSS 8.8. EPSS: 2.3% chance of exploitation in the next 30 days.

When processing callbacks that occurred during window flushing in the parent process, the associated window may die; causing a use-after-free condition. This could have led to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox ESR < 68.10, Firefox < 78, and Thunderbird < 68.10.0.

Affected products

• Canonical Ubuntu Linux: version 16.04 only; version 18.04 only; version 19.10 only; version 20.04 only
• Mozilla Firefox: before 78.0 (fixed in 78.0)
• Mozilla Firefox ESR: before 68.10 (fixed in 68.10)
• Mozilla Thunderbird: before 68.10.0 (fixed in 68.10.0)
• Opensuse Leap: version 15.1 only; version 15.2 only

Published 2020-07-09. Last modified 2026-06-17.