Description
Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
Published: 2026-08-18
Score: 9.8 Critical
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

History

Tue, 18 Aug 2026 20:30:00 +0000

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'}


Tue, 18 Aug 2026 19:00:00 +0000

Type Values Removed Values Added
Description Internally found bugs present in Firefox ESR 115.38, Firefox ESR 140.13, Firefox ESR 153.0 and Firefox 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, and Firefox ESR 153.1. Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
Title Internally found bugs fixed in Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1 and Firefox 154 Internally found bugs fixed in Thunderbird ESR 140.14, Thunderbird ESR 153.1 and Thunderbird 154
References

Tue, 18 Aug 2026 14:15:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Vendors & Products Mozilla
Mozilla firefox

Tue, 18 Aug 2026 14:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-122

Tue, 18 Aug 2026 12:45:00 +0000

Type Values Removed Values Added
Description Internally found bugs present in Firefox ESR 115.38, Firefox ESR 140.13, Firefox ESR 153.0 and Firefox 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, and Firefox ESR 153.1.
Title Internally found bugs fixed in Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1 and Firefox 154
References

cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2026-08-18T19:28:52.918Z

Reserved: 2026-08-17T11:59:24.147Z

Link: CVE-2026-74990

cve-icon Vulnrichment

Updated: 2026-08-18T19:27:44.751Z

cve-icon NVD

Status : Undergoing Analysis

Published: 2026-08-18T13:17:40.930

Modified: 2026-08-18T20:17:32.190

Link: CVE-2026-74990

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-18T14:00:13Z

Weaknesses