CVE-2026-74976: Vulnerability in Mozilla Firefox
CVE-2026-74976 is a low severity vulnerability involving JIT miscompilation in the JavaScript Engine's JIT component of Mozilla Firefox. This issue was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1. The vulnerability does not have known exploits in the wild and affects versions prior to these fixed releases.
AI Analysis
Technical Summary
This vulnerability concerns a Just-In-Time (JIT) miscompilation flaw in the JavaScript Engine's JIT component of Mozilla Firefox. The flaw could potentially lead to incorrect code execution due to the JIT compiler generating faulty machine code. Mozilla fixed this issue in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1. The CVSS v3.1 base score is 6.5, reflecting a medium severity with network attack vector, low attack complexity, no privileges required, user interaction required, unchanged scope, high confidentiality impact, and no integrity or availability impact.
Potential Impact
The vulnerability could allow an attacker to cause the JavaScript engine to miscompile code, potentially leading to unauthorized disclosure of information (high confidentiality impact). There is no known exploitation in the wild. The impact is limited to confidentiality with no integrity or availability effects.
Mitigation Recommendations
Mozilla has released official fixes 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. No additional mitigation actions are required beyond applying these updates.
CVE-2026-74976: Vulnerability in Mozilla Firefox
Description
CVE-2026-74976 is a low severity vulnerability involving JIT miscompilation in the JavaScript Engine's JIT component of Mozilla Firefox. This issue was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1. The vulnerability does not have known exploits in the wild and affects versions prior to these fixed releases.
CVSS v3.1
Score 6.5medium
Affected software
Mozilla
Firefox
Mozilla
Thunderbird
pkg:github/mozilla/firefox-esrRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability concerns a Just-In-Time (JIT) miscompilation flaw in the JavaScript Engine's JIT component of Mozilla Firefox. The flaw could potentially lead to incorrect code execution due to the JIT compiler generating faulty machine code. Mozilla fixed this issue in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1. The CVSS v3.1 base score is 6.5, reflecting a medium severity with network attack vector, low attack complexity, no privileges required, user interaction required, unchanged scope, high confidentiality impact, and no integrity or availability impact.
Potential Impact
The vulnerability could allow an attacker to cause the JavaScript engine to miscompile code, potentially leading to unauthorized disclosure of information (high confidentiality impact). There is no known exploitation in the wild. The impact is limited to confidentiality with no integrity or availability effects.
Mitigation Recommendations
Mozilla has released official fixes 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. No additional mitigation actions are required beyond applying these updates.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-08-17T11:58:57.547Z
- State
- PUBLISHED
- 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: 09/11/2026, 21:48:35 UTC
Last updated: 10/02/2026, 02:46:06 UTC
Views: 46
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