CVE-2026-4718
HIGHCVSS 8.1/10EPSS 0.30%
Last modified
CVE-2026-4718 is a high-severity vulnerability rated 8.1/10 on the CVSS scale. Undefined behavior in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.. EPSS estimates a 0.30% chance of exploitation in the next 30 days.
Description
Undefined behavior in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 140.9.0 |
| Mozilla | Firefox | < 149.0 |
| Mozilla | Thunderbird | < 140.9.0 |
| Mozilla | Thunderbird | < 149.0 |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2014864Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-20/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-22/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-23/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-24/Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2026-4718?
Undefined behavior in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
How severe is CVE-2026-4718?
CVE-2026-4718 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 0.30% probability of exploitation in the next 30 days.
How do I fix CVE-2026-4718?
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-2026-47174In Duck Site before version 1.0.1, the repository has a depl…9.5
- CVE-2026-47175Quest Bot is an opensource modern Discord Bot built for mode…2.3
- CVE-2026-47176Quest Bot is an opensource modern Discord Bot built for mode…5.7
- CVE-2026-47177Quest Bot is an opensource modern Discord Bot built for mode…5.7
- CVE-2026-47178libheif is a HEIF and AVIF file format decoder and encoder. …7.8
- CVE-2026-47179Arcane is an interface for managing Docker containers, image…7.7
- CVE-2026-47180Zeroconf is a pure Python implementation of multicast DNS se…6.5
- CVE-2026-47181PenguinMod-BackendApi is the backend api for penguinmod. Pri…8.7
- CVE-2026-47182Frappe is a full-stack web application framework. Prior to v…5.3
- CVE-2026-47183Zeroconf is a pure Python implementation of multicast DNS se…6.5
- CVE-2026-47184Zeroconf is a pure Python implementation of multicast DNS se…6.5
- CVE-2026-47185Frappe is a full-stack web application framework. Prior to 1…5.1
Are you affected by CVE-2026-4718?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST