CVE-2026-100804
Received Received - Intake

Use-After-Free Sandbox Escape in Firefox

Publication date: 2026-09-29

Last updated on: 2026-09-29

Assigner: Mozilla Corporation

Description
Sandbox escape due to use-after-free in the Preferences: Backend component. This vulnerability was fixed in 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-2026-100804
EUVD
EUVD-2026-88957

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
mozilla firefox 157

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is a sandbox escape caused by a use-after-free bug in Firefox's Preferences Backend component. A use-after-free occurs when a program tries to use memory that has already been freed, potentially allowing an attacker to execute arbitrary code or escape the browser sandbox.

Detection Guidance

This vulnerability is specific to Firefox versions before 157. To detect it, check your Firefox version using about:support in the browser or run firefox --version in the terminal. If the version is below 157, the system is vulnerable.

Impact Analysis

This vulnerability could allow an attacker to break out of the browser sandbox and execute malicious code on your system. If exploited, it may lead to unauthorized access to sensitive data, installation of malware, or further compromise of your device.

Mitigation Strategies

Update Firefox to version 157 or later immediately. Disable automatic updates temporarily if needed, but prioritize patching. Avoid using untrusted extensions or websites until updated.

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