CVE-2026-12299
MEDIUMCVSS 5.4/10EPSS 0.31%
Last modified
CVE-2026-12299 is a medium-severity vulnerability rated 5.4/10 on the CVSS scale. JIT miscompilation in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.. EPSS estimates a 0.31% chance of exploitation in the next 30 days.
Description
JIT miscompilation in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
Metrics
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 115.37.0 |
| Mozilla | Firefox | < 152.0 |
| Mozilla | Firefox | >= 140.0, < 140.12.0 |
| Mozilla | Thunderbird | < 152.0.0 |
| Mozilla | Thunderbird | >= 140.0, < 140.12.0 |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2043139Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-57/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-58/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-59/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-60/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-61/Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2026-12299?
JIT miscompilation in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
How severe is CVE-2026-12299?
CVE-2026-12299 has a CVSS score of 5.4/10 (MEDIUM severity). The EPSS model estimates a 0.31% probability of exploitation in the next 30 days.
How do I fix CVE-2026-12299?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2026
- CVE-2026-12298Memory safety bug fixed in Thunderbird 152. This vulnerabili…5.4
- CVE-2026-122984Heap-based buffer overflow in Windows Universal Disk Format …7.8
- CVE-2026-122985Improper restriction of xml external entity reference in Mic…6.1
- CVE-2026-122986Improper privilege management in Microsoft Azure Kubernetes …7.8
- CVE-2026-122987Missing authentication for critical function in Microsoft Hi…5.9
- CVE-2026-122988Improper authorization in Windows Admin Center allows an aut…8
- CVE-2026-122992In G4KLX DStarGateway and F4FXL DStarGateway before 7b75de6,…9.2
- CVE-2026-1230GitLab has remediated an issue in GitLab CE/EE affecting all…6.5
- CVE-2026-12300Memory safety bug fixed in Thunderbird 152. This vulnerabili…5.3
- CVE-2026-12301Memory safety bug fixed in Thunderbird 152. This vulnerabili…5.3
- CVE-2026-123010@twilio-labs/netlify-okta-auth through 1.0.2 relies on an un…7.2
- CVE-2026-123011STMicroelectronics st-mems-android-linux-sensors-hal before …4.2
Are you affected by CVE-2026-12299?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST