Description
Integer overflow in the Graphics component. This vulnerability was fixed in Firefox 154, 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: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

This vulnerability is an integer overflow in the graphics component of Mozilla Firefox and Thunderbird. The CVE description does not specify the exact impact, but integer overflows can cause program crashes and potential denial‑of‑service conditions.

Affected Systems

All versions of Mozilla Firefox and Thunderbird released before the patched iterations are affected. Specifically, any Firefox product earlier than version 154, as well as Firefox ESR 140.14 and all versions earlier than 140.14, and any ESR 153.1 release earlier than 153.1, are vulnerable. Likewise, any Thunderbird product earlier than version 154, Thunderbird ESR 140.14 and earlier releases, and Thunderbird ESR 153.1 and earlier releases also carry the flaw.

Risk and Exploitability

The CVSS score of 9.8 signals critical severity. The EPSS score is less than 1% and the vulnerability is not listed in the CISA KEV catalog, but the potential for a crash still poses a significant availability risk. The likely attack vector is the delivery of crafted graphic content, such as an embedded image or attachment, which would trigger the overflow when processed. This inference is based on the nature of the integer overflow in the rendering engine.

Generated by OpenCVE AI on August 21, 2026 at 20:27 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Upgrade Mozilla Firefox to version 154 or newer, or to Firefox ESR 140.14 or later. Upgrade Mozilla Thunderbird to version 154 or newer, or to Thunderbird ESR 140.14 or later.
  • If an immediate upgrade is not possible, disable hardware acceleration in the affected applications by setting gfx.direct2d.enabled to false in about:config to reduce exposure to the graphics component.
  • If updating is not feasible, contact Mozilla support for guidance on additional mitigations.

Generated by OpenCVE AI on August 21, 2026 at 20:27 UTC.

Tracking

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Advisories
Source ID Title
Debian DLA Debian DLA DLA-4750-1 firefox-esr security update
Debian DLA Debian DLA DLA-4754-1 thunderbird security update
Debian DSA Debian DSA DSA-6451-1 firefox-esr security update
Debian DSA Debian DSA DSA-6461-1 thunderbird security update
History

Wed, 19 Aug 2026 16:45:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla thunderbird
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
Vendors & Products Mozilla thunderbird

Wed, 19 Aug 2026 13:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

 ssvc

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

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'}

Wed, 19 Aug 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

threat_severity

Moderate

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

Type Values Removed Values Added
Description Integer overflow in the Graphics component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1. Integer overflow in the Graphics component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
References

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

Type Values Removed Values Added
Weaknesses CWE-190

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

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

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

Type Values Removed Values Added
Description Integer overflow in the Graphics component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1.
Title Integer overflow in the Graphics component
References

Subscriptions

Mozilla Firefox Thunderbird
cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2026-08-19T12:55:53.794Z

Reserved: 2026-08-17T11:58:31.172Z

Link: CVE-2026-74964

cve-icon Vulnrichment

Updated: 2026-08-19T12:55:19.819Z

cve-icon NVD

Status : Analyzed

Published: 2026-08-18T13:17:33.683

Modified: 2026-08-19T16:38:10.767

Link: CVE-2026-74964

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-08-18T12:23:32Z

Links: CVE-2026-74964 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-21T20:30:07Z

Weaknesses
  • CWE-190

    Integer Overflow or Wraparound