CVE-2026-109722
Received Received - Intake

JIT Miscompilation in Firefox JavaScript Engine

Publication date: 2026-10-13

Last updated on: 2026-10-13

Assigner: Mozilla Corporation

Description
JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 158, Firefox ESR 115.43, and Firefox ESR 153.5.

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Meta Information

Published
2026-10-13
Last Modified
2026-10-13
Generated
2026-10-13
AI Q&A
2026-10-13
EPSS Evaluated
N/A
NVD
CVE-2026-109722
EUVD
EUVD-2026-98642

Affected Vendors & Products

Showing 5 associated CPEs
Vendor Product Version / Range
mozilla firefox to 158 (inc)
mozilla firefox_esr to 115.43 (inc)
mozilla firefox_esr to 153.5 (inc)
mozilla firefox to 115.43 (inc)
mozilla firefox to 153.5 (inc)

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is a JIT miscompilation issue in the JavaScript Engine. JIT stands for Just-In-Time compilation, which is used to improve the performance of JavaScript code by compiling it to machine code at runtime. A miscompilation here means the engine incorrectly translates JavaScript code into machine code, potentially leading to unexpected behavior or security flaws.

Detection Guidance

Detection requires checking Firefox version. Run 'firefox --version' or check 'about:support' in Firefox. Versions below 158 or ESR 115.43/153.5 are vulnerable.

Impact Analysis

The impact could include arbitrary code execution, crashes, or unexpected behavior in applications using the affected Firefox versions. Attackers might exploit this to run malicious code on your system, steal data, or disrupt services. Users of Firefox versions before 158, Firefox ESR 115.43, or Firefox ESR 153.5 are at risk.

Mitigation Strategies

Update Firefox to version 158 or Firefox ESR to 115.43 or 153.5 immediately. Disable JavaScript if updates are not possible, but this may break functionality.

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