---
id: "CVE-2026-93515"
kind: "vulnerability"
aliases: ["CVE-2026-93515"]
title: "X.org X Server: use-after-free lets a malicious X client crash or run code"
severity: "medium"
cvss: 6.8
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["desktop", "infrastructure", "linux", "x.org", "x11", "xorg", "xwayland"]
not_affected_if: ["no-untrusted-x-clients", "wayland-only"]
published_at: "2026-10-28T13:17:29+00:00"
first_seen_at: "2026-10-28T13:33:01+00:00"
updated_at: "2026-10-28T13:34:17+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93515", "first_seen_at": "2026-10-28T13:33:01+00:00"}]
---

# X.org X Server: use-after-free lets a malicious X client crash or run code

A use-after-free in present_clear_window_notifies() in the X.org X Server before 21.1.25 and X Wayland before 24.1.14 lets a malicious X client crash the server. The sources also say it could 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 `X -version` to read the installed X.org X Server version
- Check whether the X Wayland component (Xwayland) is installed and its version with `Xwayland -version`

## Fix

- Upgrade the X.org X Server to `21.1.25` or later
- Upgrade X Wayland (Xwayland) to `24.1.14` or later

## Timeline

- 2026-10-28T13:33:01+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-93515

## From the sources

A use-after-free in present_clear_window_notifies()  in the X.org X Server before 21.1.25 and X Wayland before 24.1.14 could be used by malicious X clients to crash or potentially execute 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_