CVE-2026-100815
Received Received - Intake

Use-after-free in Firefox ESR and Firefox

Publication date: 2026-09-29

Last updated on: 2026-09-29

Assigner: Mozilla Corporation

Description
Use-after-free in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox ESR 153.4 and Firefox 157.

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Meta Information

Published
2026-09-29
Last Modified
2026-09-29
Generated
2026-09-29
AI Q&A
2026-09-29
EPSS Evaluated
N/A
NVD
CVE-2026-100815
EUVD
EUVD-2026-88794

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
mozilla firefox to 153.4 (inc)
mozilla firefox to 157 (inc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a use-after-free vulnerability in Firefox's CSS Parsing and Computation 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 ESR 153.4 and Firefox 157.

Detection Guidance

Detection requires checking Firefox version. Run 'firefox --version' or check 'about:support' in Firefox. If using Firefox ESR, verify version is 153.4 or higher. If using standard Firefox, ensure version is 157 or higher.

Impact Analysis

An attacker could exploit this to crash your browser or run malicious code on your device. This could lead to data theft, installation of malware, or unauthorized system access if you visit a specially crafted webpage.

Mitigation Strategies

Update Firefox to ESR 153.4 or Firefox 157 or later immediately. Disable automatic updates temporarily if needed, but prioritize patching. Avoid using vulnerable versions until updated.

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