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Medium 6.5Published Aug 18, 2026
CVE-2026-74976JIT miscompilation in the JavaScript Engine: JIT component
Updated under an hour ago ()
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It affects Mozilla Firefox and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 6.5 MEDIUM (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
- Weakness (CWE)
- CWE-843
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- mozilla
- NVD analysis
- Analyzed
- Record last updated
- Aug 19, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Mozilla Firefox mozilla:firefox (from the name) | 140.14 builds before 140.* not affected; 153.1 builds before 153.* not affected; from 154 not affected | CNA record |
Mozilla Thunderbird mozilla:thunderbird (from the name) | 140.14 builds before 140.* not affected; 153.1 builds before 153.* not affected; from 154 not affected | CNA record |
mozilla firefox mozilla:firefox | before 140.14.0; from 141.0 before 153.1.0 | NVD |
mozilla thunderbird mozilla:thunderbird | before 140.14.0; from 141.0 before 153.1.0 | NVD |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1952164permissions-required
- https://www.mozilla.org/security/advisories/mfsa2026-74/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-76/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-77/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-78/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-79/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-80/vendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.