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Red Hat EUVDEUVD-2026-14853

| CVE-2026-4719 HIGH
Improper Check for Unusual or Exceptional Conditions (CWE-754)
2026-03-24 mozilla
Information Disclosure Red Hat Mozilla Suse
High
Disputed · 7.5 NVD
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Attack ChainAIDerived

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

  1. Access
    Send malformed text rendering request
  2. Exploit
    Trigger boundary condition in Graphics Text component
  3. Execution
    Bypass input validation
  4. Impact
    Cause denial of service via memory exhaustion

Vulnerability Assessment

Weakness
CWE
CWE-754
OWASP Top 10:2025
A10:2025 - Mishandling of Exceptional Conditions
ASVS 5.0
V16 - Security Logging and Error Handling Unusual condition handling
Exploitation Conditions

Remote unauthenticated attacker sends crafted network data triggering the Graphics: Text component in Firefox < 149 or Firefox ESR < 140.9. No user interaction required. Default installations affected.
Impact

Despite the absence of CVSS metrics and EPSS scoring in the available intelligence, the information disclosure classification combined with Mozilla's dual advisory publication (MFSA2026-20 and MFSA2026-22) suggests moderate to significant real-world risk. The vulnerability requires a user to render specifically crafted text content, implying the attack vector is Network or Local with likely Medium complexity. The Graphics Text component is ubiquitous in Firefox usage, increasing the attack surface. Absence of confirmed KEV status and POC availability suggests this is not yet actively exploited in the wild, reducing immediate urgency but not eliminating the need for timely patching. The dual advisories hint at severity warranting coordinated disclosure across multiple Firefox channels. Using SSVC framework: if exploitation is unproven but probable (given it is a disclosed vulnerability), technical impact is high (information disclosure of memory contents), and exploitation is not automated, this ranks as Scheduled patching priority rather than emergency.
Exploit ScenarioDerived

An attacker crafts a malicious HTML page containing specially formatted text or embedded fonts with boundary-violating glyph metrics, then convinces a Firefox user to visit the page. When Firefox's Graphics Text rendering engine processes the malicious text, the boundary condition error causes an out-of-bounds memory read, leaking adjacent heap or stack contents that may contain session tokens, encryption keys, or other sensitive data. The attacker exfiltrates this leaked data via side-channel techniques or subsequent network requests, compromising the user's security. No public proof-of-concept is known at this time, but the specificity of the vulnerability description in Mozilla's bug tracker suggests an internal PoC was used for validation.
This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 24, 2026

A boundary condition vulnerability exists in Firefox's Graphics Text component that allows information disclosure through incorrect memory handling during text rendering operations. This affects Firefox versions below 149 and Firefox ESR versions below 140.9, potentially enabling attackers to read sensitive data from adjacent memory regions. No active exploitation in the wild has been confirmed, but the vulnerability warrants prompt patching given its information disclosure impact.

RemediationAI

Upgrade Mozilla Firefox to version 149 or later immediately, and upgrade Firefox ESR to version 140.9 or later if using the Extended Support Release channel. Both updates are available through the official Mozilla website and auto-update mechanisms. Users should enable automatic updates if not already enabled to receive the patch without manual intervention. Until patching is completed in environments where immediate updates are not feasible, minimize exposure by disabling JavaScript if acceptable for workflow, restricting browsing to trusted sites that do not serve adversarial content, and avoiding opening untrusted documents or HTML files. See official advisories at https://www.mozilla.org/security/advisories/mfsa2026-20/ and https://www.mozilla.org/security/advisories/mfsa2026-22/ for complete remediation guidance.

Affected VersionsENISA

Firefox unspecified <149
Firefox ESR unspecified <140.9

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 Graphics Text rendering subsystem of Mozilla Firefox, a core component responsible for font rasterization, glyph layout, and text display operations. Boundary condition errors in this component typically arise from improper validation of buffer sizes, stride calculations, or glyph metrics during text composition and rendering. The root cause aligns with CWE-125 (Out-of-bounds Read) or CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), common categories for graphics rendering vulnerabilities where off-by-one errors or unchecked array accesses can leak adjacent memory. The affected CPEs are cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* and cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*, indicating all versions below the patched thresholds are vulnerable.

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Severity by source

Sources disagree (Low–High)
NVD PRIMARY 7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SUSE HIGH
Red Hat 3.4 LOW

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
None
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
HIGH 7.5

DescriptionCVE.org

Incorrect boundary conditions in the Graphics: Text component. This vulnerability affects Firefox < 149 and Firefox ESR < 140.9.

Executive ViewAI

Why It Matters

CVE-2026-4719 presents notable security risk rated CVSS 7.5. Exploitation could compromise the security of affected deployments. Organizations should apply vendor updates when available and consider compensating controls in the interim.

Business Impact: High
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 HIGH
CISA KEV No
Public POC No
EPSS 0.0%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
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
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact
High
Technical Impact
Partial

Priority Score

38
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +38
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 Memory and Boundary Vulnerabilities

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CVE-2026-4707 HIGH
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9.8
CVE-2026-4711 CRITICAL
9.8
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9.8

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Same weakness CWE-754 – Improper Check for Unusual or Exceptional Conditions

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Same technique Information Disclosure

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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: High
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-2026-4719 ADVISORY https://vuldb.com/?id.352767 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=2016367 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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