CVE-2020-12417: Canonical Ubuntu Linux

High severity, CVSS 8.8. EPSS: 2.7% chance of exploitation in the next 30 days.

Due to confusion about ValueTags on JavaScript Objects, an object may pass through the type barrier, resulting in memory corruption and a potentially exploitable crash. *Note: this issue only affects Firefox on ARM64 platforms.* 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 68.10.0 (fixed in 68.10.0)
• 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.