CVE-2026-109720
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: WebAssembly component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

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Meta Information

Published
2026-10-13
Last Modified
2026-10-13
Generated
2026-10-19
AI Q&A
2026-10-13
EPSS Evaluated
2026-10-18
NVD
CVE-2026-109720
EUVD
EUVD-2026-98491

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
mozilla firefox to 158 (inc)
mozilla firefox_esr to 153.5 (inc)
mozilla firefox 158
mozilla firefox_esr 153.5

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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 vulnerability is a JIT miscompilation issue in the JavaScript: WebAssembly component of Firefox. It was fixed in Firefox version 158 and Firefox ESR version 153.5. JIT miscompilation can lead to incorrect code execution, potentially causing crashes or allowing arbitrary code execution.

Detection Guidance

This vulnerability is specific to Firefox and Thunderbird versions before 158 and ESR 153.5. To detect it, check your installed versions of Firefox and Thunderbird. If you are running a version older than 158 or ESR 153.5, the system is vulnerable.

Impact Analysis

This vulnerability could allow attackers to execute arbitrary code on your system by exploiting the miscompiled WebAssembly or JavaScript code. It may also cause unexpected crashes or instability in the affected Firefox browser versions.

Compliance Impact

This vulnerability does not provide specific details about compliance impacts on standards like GDPR or HIPAA. The issue involves JIT miscompilation in JavaScript: WebAssembly, which could potentially lead to memory corruption or arbitrary code execution, but no direct link to compliance violations is mentioned.

Mitigation Strategies

Update Firefox to version 158 or later and Firefox ESR to version 153.5 or later to address the JIT miscompilation vulnerability in the JavaScript: WebAssembly component.

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