Cyber Posture

CVE-2026-4706

High

Published: 24 March 2026

Published
24 March 2026
Modified
13 April 2026
KEV Added
—
Patch
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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 0.0003 7.3th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Description

Incorrect boundary conditions in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match
prevent

Directly addresses the CVE by requiring identification, reporting, and timely correction of the Canvas2D boundary condition flaw through patching to fixed Firefox and Thunderbird versions.

RA-5 Vulnerability Monitoring and Scanning partial match
detect

Facilitates detection of the known CVE-2026-4706 vulnerability in browser components via scanning to prioritize remediation efforts.

SI-5 Security Alerts, Advisories, and Directives partial match
detect

Ensures monitoring of vendor security advisories such as MFSA2026-20 to identify and apply patches for this DoS-causing boundary condition issue.

Security SummaryAI

CVE-2026-4706 involves incorrect boundary conditions in the Graphics: Canvas2D component, as documented under CWE-754. This vulnerability affects Mozilla Firefox versions prior to 149, Firefox ESR versions prior to 115.34 and 140.9, Thunderbird versions prior to 149, and Thunderbird versions prior to 140.9. It was published on 2026-03-24.

The vulnerability carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). Remote, unauthenticated attackers can exploit it over the network with low attack complexity and no user interaction required. Exploitation results in a denial-of-service condition with high availability impact, but no compromise of confidentiality or integrity.

Mozilla security advisories MFSA2026-20, MFSA2026-21, MFSA2026-22, and MFSA2026-23, along with Bugzilla entry 2015091, detail the issue. Mitigation involves updating to Firefox 149, Firefox ESR 115.34 or 140.9, Thunderbird 149, or Thunderbird 140.9, where the vulnerability has been fixed.

Details

CWE(s)
CWE-754

Affected Products

mozilla
firefox
≤ 115.34.0 · ≤ 149.0 · 128.0 — 140.9.0

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.
attack.mitre.org →
Why these techniques?

Remote exploitation of this Canvas2D boundary condition flaw directly triggers application crashes, matching T1499.004 (Application or System Exploitation) for endpoint denial of service with no C/I impact.

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

References