ZDI-CAN-30498: ZDI-26-409: X.Org Server Glamor Font Heap-based Buffer Overflow Privilege Escalation Vulnerability

Published Jul 15, 2026

Updated

This vulnerability allows local attackers to escalate privileges on affected installations of X.Org Server. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The ZDI has assigned a CVSS rating of 7.8. The following CVEs are assigned: CVE-2026-55999.

Affected Software

1 affected component

X.Org Server

Event History

Jul 15, 2026

Advisory Published

via ZDI·05:00 AM

Data Sourced

via ZDI·05:00 AM

Description

Frequently Asked Questions

What is the severity of ZDI-CAN-30498?

The severity of ZDI-CAN-30498 is rated at CVSS 7.8, indicating a high risk.

How do I fix ZDI-CAN-30498?

To fix ZDI-CAN-30498, ensure you update to the latest version of the X.Org Server that addresses this vulnerability.

What type of vulnerability is ZDI-CAN-30498?

ZDI-CAN-30498 is classified as a heap-based buffer overflow privilege escalation vulnerability.

Who can exploit ZDI-CAN-30498?

Local attackers with the ability to execute low-privileged code on the system can exploit ZDI-CAN-30498.

What component is affected by ZDI-CAN-30498?

ZDI-CAN-30498 affects the X.Org Server software.