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Red Hat CVE-2026-4705

| EUVDEUVD-2026-14825 CRITICAL
Reliance on Undefined, Unspecified, or Implementation-Defined Behavior (CWE-758)
2026-03-24 mozilla GHSA-mrxg-j2xh-wg8q
Information Disclosure Red Hat Mozilla Suse
Critical
Disputed · 9.8 NVD
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Send malformed WebRTC signaling message
  2. Exploit
    Trigger undefined behavior in parser
  3. Execution
    Corrupt memory state
  4. Impact
    Execute arbitrary code with full privileges

Vulnerability Assessment

Weakness
CWE
CWE-758
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Reliance on undefined/unspecified behavior
Exploitation Conditions

Remote unauthenticated attacker can exploit Firefox versions < 149 and Firefox ESR < 140.9 through WebRTC signaling without user interaction. No special configuration required; default browser installations are vulnerable.
Impact

The absence of a CVSS score and vector limits quantitative risk assessment, though the Information Disclosure tag indicates confidentiality impact. Without disclosed EPSS scores or KEV (Known Exploited Vulnerabilities) status, the real-world exploitation probability cannot be definitively measured. However, several factors elevate concern: first, WebRTC signaling is an attack surface exposed to untrusted web content, requiring no privilege escalation; second, information disclosure vulnerabilities in cryptographic or session negotiation contexts can compromise the security of subsequent communications; third, the involvement of undefined behavior suggests memory corruption potential, which could escalate to remote code execution. The lack of a published POC or active exploitation reports suggests this may be patched before widespread weaponization. The SSVC (Stakeholder-Specific Vulnerability Categorization) context indicates this should be prioritized for patching despite low immediate exploitation signals, given the sensitive nature of WebRTC signaling and the browser's ubiquity.
Exploit ScenarioDerived

An attacker could craft a malicious webpage or WebRTC signaling server that sends specially formatted SDP messages or ICE candidates designed to trigger undefined behavior in Firefox's signaling parser. When a user visits the page and grants WebRTC permissions (often required for video conferencing), the malformed signaling message could corrupt memory or leak sensitive data such as local IP addresses, session tokens, or other WebRTC-related metadata. No POC has been publicly disclosed at the time of this analysis, and exploitation likely requires specific knowledge of Firefox's signaling implementation internals.
Act Now Prioritize within 24-48h. Why: CRITICAL severity.
Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 24, 2026

An undefined behavior vulnerability exists in the WebRTC Signaling component of Mozilla Firefox and Firefox ESR, potentially enabling information disclosure attacks. Firefox versions prior to 149 and Firefox ESR versions prior to 140.9 are affected. While specific exploitation mechanics are not fully detailed in available public sources, the vulnerability is classified as an information disclosure issue that could allow attackers to extract sensitive data through malformed WebRTC signaling messages.

RemediationAI

Immediately upgrade to Firefox 149 or later, or Firefox ESR 140.9 or later, depending on your release track—see https://www.mozilla.org/security/advisories/mfsa2026-20/ and https://www.mozilla.org/security/advisories/mfsa2026-22/ for official guidance. For enterprise deployments unable to patch immediately, consider restricting WebRTC functionality via browser policy (disable-webrtc flag or equivalent) or implementing network-level controls to limit exposure to untrusted websites that might exploit signaling parsing flaws. Ensure automatic updates are enabled to receive this and future security patches promptly. Monitor Mozilla's security advisories for any additional details or related issues.

Affected VersionsENISA

Firefox ESR unspecified <140.9
Firefox unspecified <149

Affected Packages

euvd firefox_esr_unspecified fix: 140.9
euvd firefox_unspecified fix: 149

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 2 packages in euvd

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Technical ContextAI · show details

WebRTC (Web Real-Time Communication) is a critical browser technology enabling peer-to-peer audio, video, and data transmission directly between browsers. The signaling component is responsible for establishing and negotiating these connections through the exchange of Session Description Protocol (SDP) messages and ICE candidates. Undefined behavior in this component suggests memory safety issues—potentially use-after-free, buffer overflows, or type confusion—within the signaling state machine or message parsing logic. The vulnerability affects Mozilla Firefox (cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*) and Firefox ESR (cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*), both of which use the same Gecko rendering engine and WebRTC implementation. The CWE classification is not provided, but undefined behavior in protocol handlers typically maps to CWE-457 (Use of Uninitialized Variable) or CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer).

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Severity by source

Sources disagree (Medium–Critical)
NVD PRIMARY 9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SUSE CRITICAL
Red Hat 6.5 MEDIUM

vuln.today treats the vendor’s rating as authoritative. A higher third-party CVSS (e.g. CISA-ADP) is shown for transparency but does not drive the headline severity.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
Patch released
Mar 31, 2026 - 21:13 nvd
Patch available
CVE Published
Mar 24, 2026 - 12:30 nvd
CRITICAL 9.8

DescriptionCVE.org

Undefined behavior in the WebRTC: Signaling component. This vulnerability affects Firefox < 149 and Firefox ESR < 140.9.

Executive ViewAI

Why It Matters

CVE-2026-4705 presents critical security risk rated CVSS 9.8. Successful exploitation could critically impact the confidentiality, integrity, and availability of affected systems. Organizations should apply vendor updates immediately when available and implement compensating controls in the interim.

Business Impact: Severe
Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.

Threat Intelligence Overview

EPSS Score
0.0%
Top 97% exploitable
Data Quality
6 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment Vendor VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.0%
Patch available Yes
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Out-of-Cycle
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact
Very High
Technical Impact
Total

Priority Score

49
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +49
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Related Vulnerabilities in Firefox Multiple Component Vulnerabilities

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CVE-2026-4694 HIGH
7.5
CVE-2026-4724 CRITICAL
9.1

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Same weakness CWE-758 – Reliance on Undefined, Unspecified, or Implementation-Defined Behavior

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Same technique Information Disclosure

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7.5

Vendor StatusVendor

Debian

firefox
Release Status Fixed Version Urgency
sid vulnerable 148.0.2-1 -
(unstable) fixed (unfixed) -
firefox-esr
Release Status Fixed Version Urgency
bullseye vulnerable 115.14.0esr-1~deb11u1 -
bullseye (security) vulnerable 140.8.0esr-1~deb11u1 -
bookworm vulnerable 128.14.0esr-1~deb12u1 -
bookworm (security) vulnerable 140.8.0esr-1~deb12u1 -
trixie (security), trixie vulnerable 140.8.0esr-1~deb13u1 -
forky, sid vulnerable 140.8.0esr-1 -
(unstable) fixed (unfixed) -

SUSE

Severity: Critical
Product Status
Image SLES15-SP5-SAP-Azure-LI-BYOS Image SLES15-SP5-SAP-Azure-LI-BYOS-Production Image SLES15-SP5-SAP-Azure-VLI-BYOS Image SLES15-SP5-SAP-Azure-VLI-BYOS-Production Image SLES15-SP6-SAP-Azure-LI-BYOS Image SLES15-SP6-SAP-Azure-LI-BYOS-Production Image SLES15-SP6-SAP-Azure-VLI-BYOS Image SLES15-SP6-SAP-Azure-VLI-BYOS-Production Image SLES15-SP7-SAP-Azure-LI-BYOS-Production Image SLES15-SP7-SAP-Azure-VLI-BYOS-Production Affected
SUSE Liberty Linux 10 Fixed
SUSE Liberty Linux 8 Fixed
SUSE Liberty Linux 9 Fixed
SUSE Linux Enterprise Desktop 15 SP7 SUSE Linux Enterprise Server 15 SP7 SUSE Linux Enterprise Server for SAP Applications 15 SP7 Fixed

References

Advisories & patches
ADVISORY https://access.redhat.com/errata/RHSA-2026:5930 ADVISORY https://access.redhat.com/errata/RHSA-2026:5931 ADVISORY https://access.redhat.com/errata/RHSA-2026:5932 ADVISORY https://access.redhat.com/errata/RHSA-2026:6188 ADVISORY https://access.redhat.com/errata/RHSA-2026:6342 ADVISORY https://access.redhat.com/errata/RHSA-2026:6917 ADVISORY https://access.redhat.com/errata/RHSA-2026:7837 ADVISORY https://access.redhat.com/errata/RHSA-2026:7838 ADVISORY https://access.redhat.com/errata/RHSA-2026:7839 ADVISORY https://access.redhat.com/errata/RHSA-2026:7840 ADVISORY https://access.redhat.com/errata/RHSA-2026:7841 ADVISORY https://access.redhat.com/errata/RHSA-2026:7842 ADVISORY https://access.redhat.com/errata/RHSA-2026:7843 ADVISORY https://access.redhat.com/errata/RHSA-2026:7845 ADVISORY https://access.redhat.com/errata/RHSA-2026:7858 ADVISORY https://access.redhat.com/errata/RHSA-2026:8284 ADVISORY https://access.redhat.com/errata/RHSA-2026:8285 ADVISORY https://access.redhat.com/errata/RHSA-2026:8286 ADVISORY https://access.redhat.com/errata/RHSA-2026:8287 ADVISORY https://access.redhat.com/errata/RHSA-2026:8288 ADVISORY https://access.redhat.com/errata/RHSA-2026:8289 ADVISORY https://access.redhat.com/errata/RHSA-2026:8290 ADVISORY https://access.redhat.com/errata/RHSA-2026:8315 ADVISORY https://access.redhat.com/errata/RHSA-2026:8427 ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2026-4705 ADVISORY https://vuldb.com/?id.352751 ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:1126/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:1127/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:1163/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20978/ REF https://bugzilla.mozilla.org/show_bug.cgi?id=2014873 REF https://www.mozilla.org/security/advisories/mfsa2026-20/ REF https://www.mozilla.org/security/advisories/mfsa2026-22/ REF https://www.mozilla.org/security/advisories/mfsa2026-23/ REF https://www.mozilla.org/security/advisories/mfsa2026-24/

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