---
cve: "CVE-2026-55999"
severity: "HIGH"
cvss: 8.5
epss: "27%"
vendor: "X.org"
kev: false
exploited: false
published: "2026-07-08 09:16:29"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-13T23:23:32+02:00"
---

# CVE-2026-55999

> 8.5 HIGH

## Beschreibung

Local attackers with a X connection able to provide PCX fonts to the X 
server xorg-server before 21.2.24 and xwayland before 24.1.13 could 
cause a heap buffer overflow via SetFont due to missing glyph boundary checks.

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Hoch | good |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |
| S Scope | Verändert | bad |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- c5a47fda896aeefbf1d06a73e392a294344f9e1a (Commit)
- fbf7bac22e2c6bd627fb042742a23318263edae1 (Commit)

## Referenzen

- <https://gitlab.freedesktop.org/xorg/xserver/-/commit/fbf7bac22e2c6bd627fb042742a23318263edae1>
- <https://www.openwall.com/lists/oss-security/2026/07/08/2>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-55999) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_