CVE-2026-4699: Incorrect boundary conditions in the Layout: Text and Fonts component

Published Mar 24, 2026
·
Updated

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

Other sources

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

— MITRE

Affected Software

10 affected componentsFixes available
Mozilla Firefox<149
Mozilla Firefox ESR<115.34, <140.9
Mozilla Firefox<149
149
Mozilla Firefox ESR<115.34
115.34
Mozilla Firefox ESR<140.9
140.9
Mozilla Firefox<115.34.0
Mozilla Firefox<149.0
Mozilla Firefox>=128.0<140.9.0
Mozilla Thunderbird<140.9
140.9
Mozilla Thunderbird<149
149

Event History

Mar 24, 2026
CVE Published
via Mozilla·12:00 AM
Data Sourced
via Mozilla·12:00 AM
DescriptionSeverityAffected Software
Updated
via Mozilla·12:00 AM
Affected Software
CVE Published
via MITRE·12:30 PM
Data Sourced
via MITRE·12:30 PM
Description
Data Sourced
via Red Hat·01:03 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·01:16 PM
DescriptionSeverityWeaknessAffected Software
Apr 7, 58249
Event
via FIRST·08:43 AM

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

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Frequently Asked Questions

1

What is the severity of CVE-2026-4699?

CVE-2026-4699 is classified as a moderate severity vulnerability due to incorrect boundary conditions in the Layout: Text and Fonts component.

2

How do I fix CVE-2026-4699?

To fix CVE-2026-4699, update to Firefox version 149 or later, or Firefox ESR versions 115.34 or 140.9 and later.

3

Which versions of Firefox are affected by CVE-2026-4699?

CVE-2026-4699 affects Firefox versions earlier than 149, and Firefox ESR versions earlier than 115.34 and 140.9.

4

What components are involved in CVE-2026-4699?

CVE-2026-4699 involves incorrect boundary conditions in the Layout: Text and Fonts component of the affected Firefox versions.

5

Is CVE-2026-4699 a remote code execution vulnerability?

CVE-2026-4699 does not specifically indicate remote code execution capabilities but poses a risk due to boundary condition issues.

Company

Resources

Contact

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CVE-2026-4699 - Incorrect boundary conditions in the Layout: Text and Fonts component - SecAlerts