---
id: "CVE-2026-88812"
kind: "vulnerability"
aliases: ["CVE-2026-88812"]
title: "X.Org X Server: XKB double free lets a client run code"
severity: "high"
cvss: 7.8
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["infrastructure", "linux-desktop", "self-hosted", "x.org", "xwayland"]
not_affected_if: ["patched-version"]
published_at: "2026-10-27T18:17:38+00:00"
first_seen_at: "2026-10-27T18:33:00+00:00"
updated_at: "2026-10-27T18:34:31+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-88812", "first_seen_at": "2026-10-27T18:33:00+00:00"}]
---

# X.Org X Server: XKB double free lets a client run code

A double free in the XKB SetGeometry handling of X.Org X Server and X Wayland lets a connected client crash the server or possibly run code in the server's context. The sources describe the flaw but do not give exploit details.

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

## How to check

- `Xorg -version` or `X -version` to read the installed X.Org X Server version
- `Xwayland -version` to read the installed X Wayland version
- unknown for whether XKB SetGeometry is reachable on a given system

## Fix

- Upgrade X.Org X Server to `21.1.25` or later
- Upgrade X Wayland to `24.1.14` or later
- unknown for interim mitigations

## Timeline

- 2026-10-27T18:33:00+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-88812

## From the sources

A double free in XKB SetGeometryin X.Org X Server before 21.1.25 and X Wayland before 24.1.14 could be used by attached clients to cause a crash or potentially code in the 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_