Vulnerability · Published Mar 25, 2026 · Assigned by mitre
CVE-2026-34085
Medium 5.9
In plain English
A medium-severity security flaw in fontconfig from fontconfig project. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 3% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)0.1%top 97.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | fontconfig | no fix listed | DEBIAN-CVE-2026-34085 |
| Debian:13 | fontconfig | no fix listed | DEBIAN-CVE-2026-34085 |
| Debian:14 | fontconfig | 2.17.1-3 | DEBIAN-CVE-2026-34085 |
| Ubuntu:22.04:LTS | fontconfig | no fix listed | UBUNTU-CVE-2026-34085 |
| Ubuntu:24.04:LTS | fontconfig | no fix listed | UBUNTU-CVE-2026-34085 |
| Ubuntu:25.10 | fontconfig | no fix listed | UBUNTU-CVE-2026-34085 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| fontconfig project | fontconfig | 0 – before 2.17.1 |
Weakness: CWE-193 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L