Denial-of-Service Vulnerability in Firefox WebRTC Signaling Component
CVE-2026-4704

7.5HIGH

Key Information:

Vendor

Mozilla
Status
Firefox
Firefox Esr
Thunderbird
Vendor
CVE Published:
24 March 2026

What is CVE-2026-4704?

A Denial-of-Service vulnerability exists in the WebRTC signaling component of Mozilla's Firefox web browser. This vulnerability impacts versions prior to Firefox 149 and Firefox ESR 140.9, which could allow an attacker to disrupt service by exploiting weaknesses in the signaling process, thereby affecting user accessibility and overall browser performance. Users are encouraged to update to the latest versions to mitigate potential risks.

Affected Version(s)

Firefox < 149

Firefox ESR < 140.9

Thunderbird < 149

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2014868
https://www.mozilla.org/security/advisories/mfsa2026-20/
https://www.mozilla.org/security/advisories/mfsa2026-22/

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Evyatar Ben Asher, Keane Lucas, Nicholas Carlini, Newton Cheng, Daniel Freeman, Alex Gaynor, and Joel Weinberger using Claude from Anthropic
.