CVE-2020-12426: Mozilla Firefox

High severity, CVSS 8.8. EPSS: 1.6% chance of exploitation in the next 30 days.

Mozilla developers and community members reported memory safety bugs present in Firefox 77. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 78.

Affected products

• Mozilla Firefox: before 78.0 (fixed in 78.0)
• Opensuse Leap: version 15.1 only; version 15.2 only

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