Cyber Posture

CVE-2026-4704

High

Published: 24 March 2026

Published
24 March 2026
Modified
13 April 2026
KEV Added
Patch
CVSS Score 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0002 6.0th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Description

Denial-of-service in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

Mitigating Controls (NIST 800-53 r5)AI

prevent

Directly mitigates the vulnerability by requiring timely identification, testing, and installation of patches that fix the WebRTC signaling resource exhaustion issue.

prevent

Implements denial-of-service protections tailored to prevent resource exhaustion from remote unauthenticated malformed WebRTC signaling messages.

preventdetect

Protects resource availability by monitoring and restricting consumption to counter uncontrolled resource usage leading to crashes in the WebRTC component.

Security SummaryAI

CVE-2026-4704 is a denial-of-service vulnerability in the WebRTC Signaling component affecting Mozilla Firefox, Firefox ESR, Thunderbird, and related products. The issue, associated with CWE-400 (Uncontrolled Resource Consumption) and scored 7.5 under CVSS 3.1 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H), enables resource exhaustion leading to application crashes or significant performance degradation. It was publicly disclosed on March 24, 2026, and addressed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

Attackers can exploit this vulnerability remotely over the network with low complexity, requiring no privileges, authentication, or user interaction. Any unauthenticated remote adversary capable of sending malformed WebRTC signaling messages to a vulnerable browser or client can trigger the DoS condition, disrupting availability by consuming excessive resources in the affected component.

Mozilla's security advisories (MFSA 2026-20 through 2026-24) and the associated Bugzilla entry (bug 2014868) detail the patch deployments in the specified versions, recommending immediate upgrades to mitigate the issue. No workarounds are mentioned in the provided references.

Details

CWE(s)

Affected Products

mozilla
firefox
≤ 140.9.0 · ≤ 149.0

MITRE ATT&CK Enterprise TechniquesAI

T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
Why these techniques?

Remote unauthenticated exploitation of the WebRTC signaling vulnerability directly triggers uncontrolled resource consumption (CWE-400), enabling application exhaustion and DoS via software vulnerability exploitation.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

References