🛡️ CVE-2021-4009 on Debian — xorg-server

⚪ Unknown ✅ No Known Exploit OSV

N/A

CVSS Score

0 Low4 Medium7 High9 Critical10

Description

A flaw was found in xorg-x11-server in versions before 21.1.2 and before 1.20.14. An out-of-bounds access can occur in the SProcXFixesCreatePointerBarrier function. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Distribution advisory

This page covers CVE-2021-4009 as tracked by Debian, for the package xorg-server. The fix is available in version 2:1.20.13-3; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Affected software

DEBIAN-CVE-2021-4009 is recorded against 2 packages.

xorg-server (fixed in 2:1.20.13-3)
xwayland (fixed in 2:21.1.4-1)

Timeline and source

Published on 17 December 2021 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2021-4009 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Ubuntu

Details

Severity Unknown

CVSS Score N/A

CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CWE N/A

Public Exploit ✅ No

Source OSV

Published 2021-12-17

Updated 2026-08-12

Modified 2026-08-04

Fix URL N/A

Affected Packages

Software	From version	Fixed in
xorg-server	—	2:1.20.13-3
xwayland	—	2:21.1.4-1

References

ADVISORY https://security-tracker.debian.org/tracker/CVE-2021-4009

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