CVE-2026-74937

Analyzed Analyzed - Analysis Complete

Use-after-free in Firefox JavaScript GC

Publication date: 2026-08-18

Last updated on: 2026-08-19

Assigner: Mozilla Corporation

Description

Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-08-18

Last Modified

2026-08-19

Generated

2026-09-07

AI Q&A

2026-08-18

EPSS Evaluated

2026-09-06

NVD

CVE-2026-74937

EUVD

EUVD-2026-60675

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 154.0.0 (exc)
mozilla	thunderbird	to 154.0 (exc)
mozilla	firefox	to 153.1.0 (exc)
mozilla	thunderbird	to 153.1.0 (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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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 the JavaScript garbage collection component of Firefox. It allows an attacker to exploit memory corruption after it has been freed, potentially leading to arbitrary code execution or crashes.

Detection Guidance

Detection of this vulnerability requires checking Firefox and Firefox ESR versions. The issue was fixed in Firefox 154 and Firefox ESR 153.1. Use commands like 'firefox --version' or 'firefox-esr --version' to verify installed versions. If versions are below these thresholds, the system is vulnerable.

Impact Analysis

If exploited, this vulnerability could allow an attacker to run malicious code on your system, steal data, or cause the browser to crash. It primarily affects users of vulnerable Firefox versions.

Compliance Impact

The provided CVE data does not specify how this vulnerability impacts compliance with standards like GDPR or HIPAA. The description only mentions a use-after-free issue in Firefox's JavaScript garbage collection, fixed in versions 154 and ESR 153.1.

Mitigation Strategies

Update Firefox to version 154 or later and Firefox ESR to version 153.1 or later to address the use-after-free vulnerability in the JavaScript: GC component.

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