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Red Hat EUVDEUVD-2026-14845

| CVE-2026-4715 CRITICAL
Use of Uninitialized Resource (CWE-908)
2026-03-24 mozilla GHSA-8cfw-c9hx-8f9v
Information Disclosure Red Hat Mozilla Suse
Critical
Disputed · 9.1 NVD
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Attack ChainAIDerived

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

  1. Access
    Visit malicious webpage with crafted Canvas2D
  2. Exploit
    Trigger uninitialized memory read
  3. Execution
    Leak sensitive browser data
  4. Impact
    Cause denial of service

Vulnerability Assessment

Weakness
CWE
CWE-908
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Variable initialization
Exploitation Conditions

Remote unauthenticated attacker can exploit Firefox versions before 149 (or ESR before 140.9) by delivering malicious content leveraging the Canvas2D component. The victim must visit a malicious webpage or open crafted HTML content in an affected Firefox browser. No special configuration required.
Impact

While CVSS and CVSS vector data are not available for this CVE, the vulnerability is categorized as Information Disclosure, which typically carries moderate to high severity in the CVSS framework (though exact scoring cannot be confirmed). The vulnerability requires user interaction (visiting a malicious webpage with Canvas2D exploits) but does not require authentication or high privileges, suggesting a network-based attack vector with low complexity. As a memory disclosure issue in a widely-used browser, the real-world risk is significant despite the lack of formal CVSS rating. The fact that Mozilla released dedicated security advisories (MFSA2026-20 and MFSA2026-22) indicates this was prioritized for patching. Without KEV or public POC data in the available intelligence, the exploit likelihood cannot be definitively assessed, but the nature of memory disclosure vulnerabilities typically allows for reliable exploitation once discovered.
Exploit ScenarioDerived

A user visits a malicious website containing a specially crafted HTML5 Canvas2D script. The script performs a series of drawing operations on uninitialized Canvas buffers, causing the graphics subsystem to process uninitialized memory. The attacker's JavaScript then reads pixel data from the Canvas using getImageData(), extracting sensitive information such as previously rendered content or other sensitive data resident in graphics memory. This occurs entirely within the browser sandbox with no additional user interaction required beyond visiting the page.
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 uninitialized memory vulnerability exists in Firefox and Firefox ESR's Graphics Canvas2D component that can lead to information disclosure. Firefox versions prior to 149 and Firefox ESR versions prior to 140.9 are affected. An attacker can exploit this by crafting malicious Canvas2D operations to read uninitialized memory contents from the graphics rendering pipeline, potentially exposing sensitive data from the browser process.

RemediationAI

Immediately upgrade Mozilla Firefox to version 149 or later, and Firefox ESR to version 140.9 or later. Users unable to immediately patch should avoid visiting untrusted websites and consider disabling JavaScript in the browser settings as a temporary measure, though this significantly limits functionality. Administrators managing Firefox deployments should enable automatic updates through Group Policy (Windows) or Firefox policies.json (cross-platform) to ensure rapid patching. Verify the upgrade by checking About Firefox and confirming the version number meets the minimum requirements specified in the security advisories at https://www.mozilla.org/security/advisories/mfsa2026-20/ and https://www.mozilla.org/security/advisories/mfsa2026-22/.

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

The vulnerability resides in the Canvas2D graphics rendering component of the Gecko engine used by Mozilla Firefox. Canvas2D is a Web API that allows web pages to draw graphics via JavaScript, implemented through the Graphics subsystem. The root cause is classified as CWE (uninitialized memory), indicating that memory buffers used during Canvas2D operations are not properly initialized before use. This allows an attacker-controlled script running in a web context to access residual data from previous allocations. The affected products are identified via CPE as cpe:2.3:a:mozilla:firefox and cpe:2.3:a:mozilla:firefox_esr, affecting the entire product families below specified version thresholds.

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  • Exploit and PoC references, threat intelligence from 22 sources
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Severity by source

Sources disagree (Medium–Critical)
NVD PRIMARY 9.1 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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
None
Availability
High

Lifecycle Timeline

2
Patch released
Mar 31, 2026 - 21:13 nvd
Patch available
CVE Published
Mar 24, 2026 - 12:30 nvd
CRITICAL 9.1

DescriptionCVE.org

Uninitialized memory in the Graphics: Canvas2D component. This vulnerability affects Firefox < 149 and Firefox ESR < 140.9.

Executive ViewAI

Why It Matters

CVE-2026-4715 presents critical security risk rated CVSS 9.1. 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 96% 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
Partial

Priority Score

46
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +46
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.

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Same weakness CWE-908 – Use of Uninitialized Resource

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CVE-2015-1701 HIGH POC
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CVE-2017-0147 HIGH POC
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-2026-4715 ADVISORY https://vuldb.com/?id.352764 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=2018405 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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