---
id: "CVE-2026-93518"
kind: "vulnerability"
aliases: ["CVE-2026-93518"]
title: "X.org X server: integer truncation lets authenticated clients overflow heap"
severity: "high"
cvss: 7.8
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["bsd-desktop", "infrastructure", "linux-desktop", "x.org", "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: "2026-10-28T15:35:05+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93518", "first_seen_at": "2026-10-28T15:33:37+00:00"}]
---

# X.org X server: integer truncation lets authenticated clients overflow heap

An integer truncation bug in XkbResizeKeyType() lets an authenticated X client trigger a heap buffer overflow in the X.org X server or XWayland. An attacker can crash the server or potentially run code inside it.

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

## How to check

- Run `Xorg -version` or `X -version` and compare against `21.1.25`
- Run `Xwayland -version` and compare against `24.1.14`
- Check your distribution's package manager for the installed xorg-server or xwayland version

## Fix

- Upgrade xorg-server to `21.1.25` or later
- Upgrade XWayland to `24.1.14` or later
- Install the distribution's xorg-server or xwayland security update when available

## Timeline

- 2026-10-28T15:33:37+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-93518

## From the sources

An integer truncation issue in XkbResizeKeyType() that could lead to a heap buffer overflow by authenticated X clients in X.org X server before 21.1.25 and XWayland before 24.1.14 could be exploited for crashes or potential code execution in the X server.

---

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