---
id: "CVE-2026-93520"
kind: "vulnerability"
aliases: ["CVE-2026-93520"]
title: "X.org X server: heap overflow lets authenticated clients run code"
severity: "high"
cvss: 7.8
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["infrastructure", "linux-desktop", "self-hosted", "x11", "xwayland"]
not_affected_if: ["no-x-server", "wayland-only"]
published_at: "2026-10-28T15:17:10+00:00"
first_seen_at: "2026-10-28T15:33:37+00:00"
updated_at: "2026-10-28T15:35:04+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93520", "first_seen_at": "2026-10-28T15:33:37+00:00"}]
---

# X.org X server: heap overflow lets authenticated clients run code

A size mismatch between XkbAllocNames and ChangeKeycodeRange in the X.org X server and XWayland causes a heap buffer overflow. An authenticated X client can crash the server or potentially execute code in the X server context.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- `Xorg -version` or `Xwayland -version` to read the installed server version
- unknown

## Fix

- Upgrade the X.org X server to `2.1.25` or later
- Upgrade XWayland to `24.1.14` or later

## Timeline

- 2026-10-28T15:33:37+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-93520

## From the sources

A heap buffer overflow caused by mismatching size calculations between XkbAllocNames and  ChangeKeycodeRange in X.org X server before 2.1.25 and XWayland before 24.1.14 could be used by authenticated X clients to crash or potentially execute code in X server context.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_