CVE-2026-16412

Memory safety bugs fixed in Thunderbird ESR 140.13 and Thunderbird 153

Published Jul 21, 2026 CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed
Description
Memory safety bugs present in Thunderbird ESR 140.12 and Thunderbird 152. 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 was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4695-1 firefox-esr security update
Debian DLA Debian DLA DLA-4727-1 thunderbird security update
Debian DSA Debian DSA DSA-6394-1 firefox-esr security update
Debian DSA Debian DSA DSA-6418-1 thunderbird security update
History
Type Values Removed Values Added
Description Memory safety bugs present in Firefox ESR 140.12 and Firefox 152. 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 was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13. Memory safety bugs present in Thunderbird ESR 140.12 and Thunderbird 152. 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 was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
Title Memory safety bugs fixed in Firefox ESR 140.13 and Firefox 153 Memory safety bugs fixed in Thunderbird ESR 140.13 and Thunderbird 153
Type Values Removed Values Added
Description Memory safety bugs present in Thunderbird ESR 140.12 and Thunderbird 152. 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 was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13. Memory safety bugs present in Firefox ESR 140.12 and Firefox 152. 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 was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
Title Memory safety bugs fixed in Thunderbird ESR 140.13 and Thunderbird 153 Memory safety bugs fixed in Firefox ESR 140.13 and Firefox 153
Type Values Removed Values Added
Description Memory safety bugs present in Firefox ESR 140.12 and Firefox 152. 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 was fixed in Firefox 153 and Firefox ESR 140.13. Memory safety bugs present in Thunderbird ESR 140.12 and Thunderbird 152. 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 was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
Title Memory safety bugs fixed in Firefox ESR 140.13 and Firefox 153 Memory safety bugs fixed in Thunderbird ESR 140.13 and Thunderbird 153
References
Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Vendors & Products Mozilla
Mozilla firefox
Type Values Removed Values Added
Weaknesses CWE-119
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
mozilla
Published
Updated
Oct 21, 2026, 1:49 PM
Reserved
Jul 20, 2026, 9:57 PM
Status
Modified
Published
Jul 21, 2026, 1:17 PM
Modified
Oct 21, 2026, 2:17 PM
Severity
Important
Public date
Jul 21, 2026, 12:38 PM