CVE-2020-6819

Mozilla: Use-after-free while running the nsDocShell destructor

Published Apr 24, 2020 CVSS 3.1 · 8.1 High EPSS 3.0% KEV · Listed
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.

Remediation

No solution or workaround provided in the CVE record

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
History
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
Type Values Removed Values Added
Metrics kev

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

ssvc

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

Weaknesses

Sources

Status
PUBLISHED
Assigner
mozilla
Published
Updated
Oct 21, 2025, 11:35 PM
Reserved
Jan 10, 2020, 12:00 AM
Status
Analyzed
Published
Apr 24, 2020, 4:15 PM
Modified
Jun 17, 2026, 3:23 AM
Severity
Critical
Public date
Apr 3, 2020, 12:00 AM