CVE-2020-6800: Canonical Ubuntu Linux

High severity, CVSS 8.8. EPSS: 2.4% chance of exploitation in the next 30 days.

Mozilla developers and community members reported memory safety bugs present in Firefox 72 and Firefox ESR 68.4. 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. In general, these flaws cannot be exploited through email in the Thunderbird product because scripting is disabled when reading mail, but are potentially risks in browser or browser-like contexts. This vulnerability affects Thunderbird < 68.5, Firefox < 73, and Firefox < ESR68.5.

Affected products

• Canonical Ubuntu Linux: version 16.04 only; version 18.04 only; version 19.10 only
• Mozilla Firefox: before 73.0 (fixed in 73.0)
• Mozilla Firefox ESR: before 68.5.0 (fixed in 68.5.0)
• Mozilla Thunderbird: before 68.5.0 (fixed in 68.5.0)

Published 2020-03-02. Last modified 2026-06-17.