CVE-2026-34085
Received Received - Intake
Off-by-One Write in fontconfig Sfnt Handling Causes Code Execution

Publication date: 2026-03-25

Last updated on: 2026-03-27

Assigner: MITRE

Description
fontconfig before 2.17.1 has an off-by-one error in allocation during sfnt capability handling, leading to a one-byte out-of-bounds write, and potentially a crash or code execution. This is in FcFontCapabilities in fcfreetype.c.
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Meta Information
Published
2026-03-25
Last Modified
2026-03-27
Generated
2026-06-16
AI Q&A
2026-03-25
EPSS Evaluated
2026-06-15
NVD
CVE-2026-34085
EUVD
EUVD-2026-15934
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
fontconfig_project fontconfig to 2.17.1 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-193 A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.
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Executive Summary

This vulnerability exists in fontconfig versions before 2.17.1. It is caused by an off-by-one error in memory allocation during the handling of sfnt capabilities in the function FcFontCapabilities within the file fcfreetype.c. This error leads to a one-byte out-of-bounds write, which can potentially cause a crash or allow code execution.

Impact Analysis

The vulnerability can lead to a one-byte out-of-bounds write, which may cause the affected application to crash or, in a worst-case scenario, allow an attacker to execute arbitrary code. This can compromise the stability and security of systems using vulnerable versions of fontconfig.

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