CVE-2026-74943

Modified Modified - Updated After Analysis

Use-after-Free in Firefox Graphics ImageLib Component

Publication date: 2026-08-18

Last updated on: 2026-08-21

Assigner: Mozilla Corporation

Description

Use-after-free in the Graphics: ImageLib component. 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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-18

Last Modified

2026-08-21

Generated

2026-09-07

AI Q&A

2026-08-18

EPSS Evaluated

2026-09-06

NVD

CVE-2026-74943

EUVD

EUVD-2026-60750

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 115.39.0 (exc)
mozilla	firefox	From 116.0 (inc) to 140.14.0 (exc)
mozilla	firefox	From 141.0 (inc) to 153.1.0 (exc)
mozilla	thunderbird	From 141.0 (inc) to 153.1.0 (exc)
mozilla	thunderbird	to 140.14.0 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-416	The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Attack-Flow Graph

Executive Summary

This is a use-after-free vulnerability in Firefox's Graphics: ImageLib component. Use-after-free means the software tries to use memory after it has been freed, which can lead to crashes or arbitrary code execution. It was fixed in Firefox 154 and several Firefox ESR versions.

Detection Guidance

Detecting this vulnerability requires checking Firefox version. Run 'firefox --version' or check 'about:support' in Firefox. If version is below 154 (standard) or 115.39/140.14/153.1 (ESR), the system is vulnerable.

Impact Analysis

An attacker could exploit this to crash your browser or run malicious code on your system. This could allow them to steal data, install malware, or take control of your device if you visit a specially crafted webpage.

Compliance Impact

The provided CVE data does not specify how this vulnerability affects compliance with standards like GDPR or HIPAA. The description only mentions a use-after-free issue in Firefox's Graphics: ImageLib component, fixed in newer versions.

Mitigation Strategies

Update Firefox to version 154 or Firefox ESR to 115.39, 140.14, or 153.1 immediately. Disable automatic image processing in Firefox settings as a temporary workaround if updates are not immediately possible.

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