CVE-2026-84126
MEDIUMCVSS 4.3/10EPSS 0.19%
Last modified
CVE-2026-84126 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. Incorrect boundary conditions in the Layout: Grid component. This vulnerability was fixed in Firefox 155 and Thunderbird 155.. EPSS estimates a 0.19% chance of exploitation in the next 30 days.
Description
Incorrect boundary conditions in the Layout: Grid component. This vulnerability was fixed in Firefox 155 and Thunderbird 155.
Metrics
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 155.0.0 |
| Mozilla | Thunderbird | < 155.0 |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2063893Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-82/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-86/Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
What is CVE-2026-84126?
Incorrect boundary conditions in the Layout: Grid component. This vulnerability was fixed in Firefox 155 and Thunderbird 155.
How severe is CVE-2026-84126?
CVE-2026-84126 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 0.19% probability of exploitation in the next 30 days.
How do I fix CVE-2026-84126?
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.
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Are you affected by CVE-2026-84126?
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Scan your code nowSource: NVD / NIST