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Firefox Esr CVE-2026-4699

| EUVDEUVD-2026-14815 HIGH
Improper Check for Unusual or Exceptional Conditions (CWE-754)
2026-03-24 mozilla GHSA-2qjw-h8g8-r86f
7.5
CVSS 3.1 · NVD
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Severity by source

NVD PRIMARY
7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SUSE
HIGH
qualitative
Red Hat
7.5 HIGH
qualitative

Primary rating from NVD.

CVSS VectorNVD

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

Lifecycle Timeline

4
Patch released
Mar 31, 2026 - 21:13 nvd
Patch available
EUVD ID Assigned
Mar 24, 2026 - 12:45 euvd
EUVD-2026-14815
Analysis Generated
Mar 24, 2026 - 12:45 vuln.today
CVE Published
Mar 24, 2026 - 12:30 nvd
HIGH 7.5

DescriptionNVD

Incorrect boundary conditions in the Layout: Text and Fonts component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, and Firefox ESR < 140.9.

AnalysisAI

A boundary condition vulnerability exists in Firefox's Layout: Text and Fonts component that can lead to information disclosure. This affects Firefox versions below 149, Firefox ESR versions below 115.34, and Firefox ESR versions below 140.9. An attacker could exploit incorrect boundary handling in text and font rendering to potentially disclose sensitive information from memory, though specific exploitation details and active exploitation status are not publicly documented in the available intelligence.

Technical ContextAI

The vulnerability resides in the Layout subsystem of Firefox, specifically in the text and fonts rendering component which handles boundary validation when processing typographic data and font metrics. Boundary condition vulnerabilities (related to CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer) occur when software fails to properly validate that operations stay within defined limits, potentially allowing out-of-bounds memory access. The affected CPE strings indicate this impacts the Mozilla Firefox application across all versions prior to the specified thresholds, as well as both Firefox Extended Support Release (ESR) branches (115.x and 140.x series). The text and font layout engine is a core rendering component that processes untrusted content from web pages, making it a high-value attack surface.

RemediationAI

Update Firefox to version 149 or later, or update Firefox ESR to version 115.34 or later or version 140.9 or later, depending on which branch is in use. The specific advisory URLs are available at https://www.mozilla.org/security/advisories/mfsa2026-20/, https://www.mozilla.org/security/advisories/mfsa2026-21/, and https://www.mozilla.org/security/advisories/mfsa2026-22/ for detailed patch information. Mozilla's update mechanism typically provides automatic patching for most users; however, organizations with managed deployments should verify patch deployment across all Firefox installations. Until patching is completed, users should avoid visiting untrusted websites or opening suspicious documents in Firefox, as the vulnerability may be triggered through specially crafted web content that exploits the text and font layout boundary condition. The underlying bug tracking information is available at https://bugzilla.mozilla.org/show_bug.cgi?id=2021863 for technical details.

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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

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CVE-2026-4699 vulnerability details – vuln.today

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