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Firefox CVE-2026-6776

| EUVDEUVD-2026-24117 HIGH
Buffer Overflow (CWE-119)
2026-04-21 mozilla GHSA-cr7m-q2pr-wwq7
Mozilla Buffer Overflow Red Hat Suse
High
Disputed · 7.8 NVD
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Severity by source

Sources disagree (Low–High)
NVD PRIMARY
7.8 HIGH
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
SUSE
HIGH
qualitative
Red Hat
3.4 LOW
qualitative

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

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

8
Patch released
Apr 29, 2026 - 02:30 nvd
Patch available
Analysis Updated
Apr 22, 2026 - 00:33 vuln.today
v2 (cvss_changed)
Re-analysis Queued
Apr 22, 2026 - 00:22 vuln.today
cvss_changed
Analysis Generated
Apr 21, 2026 - 16:29 vuln.today
CVSS changed
Apr 21, 2026 - 15:22 NVD
7.8 (HIGH)
EUVD ID Assigned
Apr 21, 2026 - 13:15 euvd
EUVD-2026-24117
Analysis Generated
Apr 21, 2026 - 13:15 vuln.today
CVE Published
Apr 21, 2026 - 12:41 nvd
HIGH 7.8

DescriptionCVE.org

Incorrect boundary conditions in the WebRTC: Networking component. This vulnerability was fixed in Firefox 150 and Firefox ESR 140.10.

AnalysisAI

Buffer overflow in Firefox WebRTC networking component allows local attackers to execute arbitrary code with high impact to confidentiality, integrity, and availability. Affects Firefox versions prior to 150 and Firefox ESR prior to 140.10. No public exploit identified at time of analysis. CVSS 7.8 reflects high severity but requires local access and user interaction, limiting remote attack surface. Mozilla has released patches in Firefox 150 and Firefox ESR 140.10.

Technical ContextAI

This vulnerability affects Mozilla Firefox's WebRTC (Web Real-Time Communication) networking component, which handles peer-to-peer audio, video, and data communication in web browsers. The root cause is CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), indicating incorrect boundary condition checks that allow buffer overflow attacks. The CPE string (cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*) confirms the vulnerability exists in the core Firefox application. WebRTC networking code processes untrusted data from remote peers and media streams, making boundary validation critical for security. Buffer overflows in this component can occur when parsing malformed RTP packets, STUN/TURN messages, or SDP negotiation data without proper size validation.

RemediationAI

Upgrade to Firefox 150 or later for standard release channel users, as confirmed by Mozilla Security Advisory MFSA2026-30 and related advisories at https://www.mozilla.org/security/advisories/mfsa2026-30/. Enterprise users on the ESR channel should upgrade to Firefox ESR 140.10 or later per MFSA2026-32 at https://www.mozilla.org/security/advisories/mfsa2026-32/. If immediate patching is not feasible, implement compensating controls: disable WebRTC functionality via about:config by setting media.peerconnection.enabled to false (trade-off: breaks video conferencing and real-time communication features in web applications like Google Meet, Zoom web clients, and WebRTC-based services), restrict user ability to open untrusted local HTML files through application control policies, and deploy endpoint detection solutions monitoring for Firefox process anomalies. For enterprise environments, consider temporarily blocking WebRTC traffic at the network perimeter if the feature is not business-critical, though this does not address local file-based exploitation vectors.

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Same weakness CWE-119 – Buffer Overflow

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7.8
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CVE-2015-2426 HIGH POC
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8.8
CVE-2017-11774 HIGH POC
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Same technique Buffer Overflow

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CVE-2017-7269 CRITICAL POC
9.8
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CVE-2009-0927 HIGH POC
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CVE-2012-1889 HIGH POC
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CVE-2017-11882 HIGH POC
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CVE-2010-3333 HIGH POC
7.8

Vendor StatusVendor

SUSE

Severity: High
Product Status
SUSE Liberty Linux 10 Fixed
SUSE Liberty Linux 8 Fixed
SUSE Liberty Linux 9 Fixed
SUSE Linux Enterprise Server 16.0 SUSE Linux Enterprise Server for SAP applications 16.0 Fixed
openSUSE Leap 16.0 Fixed

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CVE-2026-6776 vulnerability details – vuln.today
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