CVE-2026-100772

Analyzed Analyzed - Analysis Complete

Use-after-free in Firefox ESR and Firefox

Publication date: 2026-09-29

Last updated on: 2026-10-06

Assigner: Mozilla Corporation

Description

Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-09-29

Last Modified

2026-10-06

Generated

2026-10-19

AI Q&A

2026-09-29

EPSS Evaluated

2026-10-18

NVD

CVE-2026-100772

EUVD

EUVD-2026-88924

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	From 154.0.0 (inc) to 157.0.0 (exc)
mozilla	thunderbird	From 154.0 (inc) to 157.0 (exc)
mozilla	thunderbird	From 140.0 (inc) to 140.17.0 (exc)
mozilla	thunderbird	From 153.0 (inc) to 153.4.0 (exc)
mozilla	firefox	From 140.0.0 (inc) to 140.17.0 (exc)
mozilla	firefox	From 153.0 (inc) to 153.4.0 (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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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 DOM: Core & HTML component. Use-after-free occurs when a program continues to use a pointer after freeing the memory it points to, potentially leading to crashes or arbitrary code execution.

Detection Guidance

This vulnerability is specific to Firefox browsers and can be detected by checking the installed version. If you are running Firefox ESR 153.4 or earlier, Firefox 157 or earlier, or Firefox ESR 140.17 or earlier, your system is vulnerable.

Impact Analysis

An attacker could exploit this to crash your browser or run malicious code on your system. This could lead to data theft, installation of malware, or unauthorized system access if combined with other vulnerabilities.

Compliance Impact

This vulnerability could potentially lead to unauthorized access or data breaches due to memory corruption, which may violate data protection requirements under GDPR or HIPAA if exploited. However, the provided CVE details do not explicitly link the issue to compliance impacts.

Mitigation Strategies

Update Firefox ESR to version 153.4 or later, Firefox to version 157 or later, or Firefox ESR 140.17 or later to address the use-after-free vulnerability in the DOM: Core & HTML component.

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