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.

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Tracking

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Advisories
Source ID Title
Debian DLA Debian DLA DLA-2170-1 firefox-esr security update
Debian DLA Debian DLA DLA-2172-1 thunderbird security update
Debian DSA Debian DSA DSA-4653-1 firefox-esr security update
Debian DSA Debian DSA DSA-4656-1 thunderbird security update
EUVD EUVD EUVD-2020-27963 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.
Ubuntu USN Ubuntu USN USN-4317-1 Firefox vulnerabilities
Ubuntu USN Ubuntu USN USN-4328-1 Thunderbird vulnerabilities
Ubuntu USN Ubuntu USN USN-4335-1 Thunderbird vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 04 Nov 2025 14:45:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
Vendors & Products Mozilla firefox Esr

Wed, 22 Oct 2025 00:15:00 +0000


Tue, 21 Oct 2025 20:30:00 +0000


Tue, 21 Oct 2025 19:30:00 +0000


Fri, 07 Feb 2025 13:15:00 +0000

Type Values Removed Values Added
Metrics kev

{'dateAdded': '2021-11-03'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'active', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 14 Aug 2024 00:45:00 +0000

Type Values Removed Values Added
References

cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2025-10-21T23:35:45.566Z

Reserved: 2020-01-10T00:00:00.000Z

Link: CVE-2020-6819

cve-icon Vulnrichment

Updated: 2024-08-04T09:11:05.160Z

cve-icon NVD

Status : Analyzed

Published: 2020-04-24T16:15:13.370

Modified: 2025-11-04T14:34:52.090

Link: CVE-2020-6819

cve-icon Redhat

Severity : Critical

Publid Date: 2020-04-03T00:00:00Z

Links: CVE-2020-6819 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses