CVE-2026-34085

5.9 MEDIUM 0.1% exploit odds Fix listed Memory safety

What it is

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.

At a glance

Exploitability: Can be exploited locally on the machine without logging in. Limited direct impact.
Exploit odds: 0.1% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-03-25 17:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 10:38 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.1% in the next 30 days (EPSS).
Severity: 5.9 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-03-25 17:17 UTC
Last modified: 2026-06-17 10:38 UTC
Exploit probability: 0.1% · EPSS, next 30 days
Weakness: CWE-193
Record status: Analyzed

Affected

Fontconfig Project Fontconfig 2.17.0

Attack profile CVSS 3.1 · 5.9

Attack vector: Local
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: Low

Raw vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-34085.md and follow it. Check whether this project is affected by CVE-2026-34085. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record