CVE-2020-6825: Mozilla Firefox

Critical severity, CVSS 9.8. EPSS: 2.2% chance of exploitation in the next 30 days.

Mozilla developers and community members Tyson Smith and Christian Holler reported memory safety bugs present in Firefox 74 and Firefox ESR 68.6. 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 < 68.7.0, Firefox ESR < 68.7, and Firefox < 75.

Affected products

• Mozilla Firefox: before 75.0 (fixed in 75.0)
• Mozilla Firefox ESR: before 68.7.0 (fixed in 68.7.0)
• Mozilla Thunderbird: before 68.7.0 (fixed in 68.7.0)

Published 2020-04-24. Last modified 2026-06-17.