CVE-2026-74976: Vulnerability in Mozilla Firefox
JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
AI Analysis
Technical Summary
CVE-2026-74976 is a vulnerability caused by just-in-time (JIT) miscompilation within the JavaScript Engine's JIT component in Mozilla Firefox. This flaw could potentially lead to incorrect code execution due to the JIT compiler generating faulty machine code. The issue was addressed and fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1 as part of a broader security update that included multiple high, moderate, and low impact fixes. The vendor advisory explicitly lists this vulnerability as low impact and confirms the availability of patches.
Potential Impact
The impact of CVE-2026-74976 is considered low according to the Mozilla advisory. While JIT miscompilation can theoretically cause incorrect execution of JavaScript code, no evidence of exploitation in the wild has been reported. The vulnerability was fixed in recent Firefox releases, mitigating any potential risk to users who have applied the updates.
Mitigation Recommendations
Mozilla has released official patches for this vulnerability in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1. Users and administrators should update to these versions or later to remediate the issue. Since the vulnerability is fixed in these versions, no additional mitigation steps are required beyond applying the official updates.
CVE-2026-74976: Vulnerability in Mozilla Firefox
Description
JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
Affected software
pkg:github/mozilla/firefox-esrRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-74976 is a vulnerability caused by just-in-time (JIT) miscompilation within the JavaScript Engine's JIT component in Mozilla Firefox. This flaw could potentially lead to incorrect code execution due to the JIT compiler generating faulty machine code. The issue was addressed and fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1 as part of a broader security update that included multiple high, moderate, and low impact fixes. The vendor advisory explicitly lists this vulnerability as low impact and confirms the availability of patches.
Potential Impact
The impact of CVE-2026-74976 is considered low according to the Mozilla advisory. While JIT miscompilation can theoretically cause incorrect execution of JavaScript code, no evidence of exploitation in the wild has been reported. The vulnerability was fixed in recent Firefox releases, mitigating any potential risk to users who have applied the updates.
Mitigation Recommendations
Mozilla has released official patches for this vulnerability in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1. Users and administrators should update to these versions or later to remediate the issue. Since the vulnerability is fixed in these versions, no additional mitigation steps are required beyond applying the official updates.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-08-17T11:58:57.547Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-74/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-76/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-77/","vendor":"Mozilla"}]
Threat ID: 6a84550bc6e8be03323676b4
Added to database: 08/18/2026, 12:50:19 UTC
Last enriched: 08/18/2026, 13:25:41 UTC
Last updated: 08/18/2026, 19:05:04 UTC
Views: 4
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