CVE-2026-16396
HIGHCVSS 8.8/10EPSS 0.33%
Last modified
CVE-2026-16396 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. Privilege escalation in WebExtensions. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.. EPSS estimates a 0.33% chance of exploitation in the next 30 days.
Description
Privilege escalation in WebExtensions. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
Metrics
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 140.13.0 |
| Mozilla | Firefox | < 153.0.0 |
| Mozilla | Thunderbird | < 140.13.0 |
| Mozilla | Thunderbird | >= 141.0, < 153.0 |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2047240Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-68/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-70/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-71/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-72/Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2026-16396?
Privilege escalation in WebExtensions. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
How severe is CVE-2026-16396?
CVE-2026-16396 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.33% probability of exploitation in the next 30 days.
How do I fix CVE-2026-16396?
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-2026-16390Mitigation bypass in the Enterprise Policies component. This…9.1
- CVE-2026-16391Information disclosure in the Storage: IndexedDB component. …7.5
- CVE-2026-16392JIT miscompilation in the JavaScript Engine: JIT component. …9.1
- CVE-2026-16393Incorrect boundary conditions in the Graphics: WebGPU compon…9.1
- CVE-2026-16394Mitigation bypass in the DOM: Security component. This vulne…9.1
- CVE-2026-16395Integer overflow in the Audio/Video component. This vulnerab…9.8
- CVE-2026-16397Clickjacking issue in the WebExtensions component in Firefox…6.5
- CVE-2026-16398Site isolation issue in the Graphics component. This vulnera…7.5
- CVE-2026-16399Site isolation issue in the DOM: Navigation component. This …7.5
- CVE-2026-1640The Taskbuilder – WordPress Project Management & Task Manage…4.3
- CVE-2026-16400Information disclosure in the DOM: Security component. This …7.5
- CVE-2026-16401Privilege escalation in the Data Loss Prevention component. …8.8
Are you affected by CVE-2026-16396?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST