CVE-2020-15683: Debian Linux

Critical severity, CVSS 9.8. EPSS: 2.7% chance of exploitation in the next 30 days.

Mozilla developers and community members reported memory safety bugs present in Firefox 81 and Firefox ESR 78.3. 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 ESR < 78.4, Firefox < 82, and Thunderbird < 78.4.

Affected products

• Debian Debian Linux: version 9.0 only; version 10.0 only
• Mozilla Firefox: before 82.0 (fixed in 82.0)
• Mozilla Firefox ESR: before 78.4 (fixed in 78.4)
• Mozilla Thunderbird: before 78.4 (fixed in 78.4)
• Opensuse Leap: version 15.1 only; version 15.2 only

Published 2020-10-22. Last modified 2026-06-17.