CVE-2020-6814: Canonical Ubuntu Linux

Critical severity, CVSS 9.8. EPSS: 1.9% chance of exploitation in the next 30 days.

Mozilla developers reported memory safety bugs present in Firefox and Thunderbird 68.5. 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 Thunderbird < 68.6, Firefox < 74, Firefox < ESR68.6, and Firefox ESR < 68.6.

Affected products

• Canonical Ubuntu Linux: version 16.04 only; version 18.04 only; version 19.10 only
• Mozilla Firefox: before 74.0 (fixed in 74.0)
• Mozilla Firefox ESR: before 68.6.0 (fixed in 68.6.0)
• Mozilla Thunderbird: before 68.6.0 (fixed in 68.6.0)

Published 2020-03-25. Last modified 2026-06-17.