CVE-2020-6819

HighCVSS 8.1/10Known exploited (CISA KEV)Last modified Jun 17, 2026

Description

Under certain conditions, when running the nsDocShell destructor, a race condition can cause a use-after-free. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Thunderbird < 68.7.0, Firefox < 74.0.1, and Firefox ESR < 68.6.1.

Metrics

CVSS 3.1 8.1/10CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Weakness enumeration

CWE-362 CWE-416

Affected software

Vendor	Product	Versions
Mozilla	Thunderbird	>= unspecified, < 68.7.0
Mozilla	Firefox	>= unspecified, < 74.0.1
Mozilla	Firefox ESR	>= unspecified, < 68.6.1

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1620818Exploit, Issue Tracking
https://usn.ubuntu.com/4335-1/Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2020-11/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-14/Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1620818Exploit, Issue Tracking
https://usn.ubuntu.com/4335-1/Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2020-11/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-14/Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-6819US Government Resource

Timeline

Published: Apr 24, 2020
Last modified: Jun 17, 2026
Added to CISA KEV: Nov 3, 2021
NVD status: Analyzed

Related CVEs from 2020

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