CVE-2026-4718: Undefined behavior in the WebRTC: Signaling component
Undefined behavior in the WebRTC: Signaling component. This vulnerability affects Firefox < 149 and Firefox ESR < 140.9.
Other sources
Undefined behavior in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
— MITRE
Affected Software
Event History
Parent advisories
This vulnerability appears in the following advisories.
Peer vulnerabilities
Found alongside the following vulnerabilities.
- CVE-2026-4684
- CVE-2026-4685
- CVE-2026-4686
- CVE-2026-4687
- CVE-2026-4688
- CVE-2026-4689
- CVE-2026-4690
- CVE-2026-4691
- CVE-2026-4692
- CVE-2026-4693
- CVE-2026-4694
- CVE-2026-4695
- CVE-2026-4696
- CVE-2026-4697
- CVE-2026-4698
- CVE-2026-4699
- CVE-2026-4700
- CVE-2026-4701
- CVE-2026-4722
- CVE-2026-4702
- CVE-2026-4723
- CVE-2026-4724
- CVE-2026-4704
- CVE-2026-4705
- CVE-2026-4706
- CVE-2026-4707
- CVE-2026-4708
- CVE-2026-4709
- CVE-2026-4710
- CVE-2026-4711
- CVE-2026-4725
- CVE-2026-4712
- CVE-2026-4713
- CVE-2026-4714
- CVE-2026-4715
- CVE-2026-4716
- CVE-2026-4717
- CVE-2026-4726
- CVE-2025-59375
- CVE-2026-4727
- CVE-2026-4728
- CVE-2026-4718
- CVE-2026-4719
- CVE-2026-4720
- CVE-2026-4729
- CVE-2026-4721
- CVE-2026-3889
- CVE-2026-4371
Frequently Asked Questions
What is the severity of CVE-2026-4718?
The severity of CVE-2026-4718 is classified as critical due to undefined behavior in the WebRTC signaling component.
How do I fix CVE-2026-4718?
To fix CVE-2026-4718, update to Firefox version 149 or higher, or Firefox ESR version 140.9 or higher.
What software does CVE-2026-4718 affect?
CVE-2026-4718 affects Mozilla Firefox versions lower than 149 and Mozilla Firefox ESR versions lower than 140.9.
What is the impact of CVE-2026-4718?
The impact of CVE-2026-4718 includes potential exploitation through undefined behavior, which can lead to security breaches.
Is CVE-2026-4718 still a concern if I am using the latest version of Firefox?
If you are using the latest version of Firefox or Firefox ESR above the specified versions, CVE-2026-4718 is not a concern for you.