CVE-2026-109904

X.Org Server XRes QueryClientIds Request Size Overflow

Published Nov 13, 2026 CVSS 4.0 · 6.9 Medium EPSS n/a KEV · Not listed

Description

A buffer overread caused by an integer-overflow in Proc/SProcXResQueryClientIds in X.Org xwayland before 24.1.15 and X Server before 21.1.26 could be used by attackers on authenticated X clients to crash the server or leak out information.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

X.Org

xorg-x11-server

unaffected

Version	Status	Constraints
`0`	affected	< 21.1.26

X.Org

xwayland

unaffected

Version	Status	Constraints
`0`	affected	< 24.1.15

No data.

No data available yet.

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

No advisories available

Metrics

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://gitlab.freedesktop.org/xorg/xserver/-/commit/ff754b812597177412f2e2fa2b1dd1eecbeb75cf

History

Nov 13, 2026 10:45 AM Description updated. Title updated. First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		A buffer overread caused by an integer-overflow in Proc/SProcXResQueryClientIds in X.Org xwayland before 24.1.15 and X Server before 21.1.26 could be used by attackers on authenticated X clients to crash the server or leak out information.
Title		X.Org Server XRes QueryClientIds Request Size Overflow
First Time appeared		X.org X.org xorg-x11-server X.org xwayland
Weaknesses		CWE-126
CPEs		cpe:2.3:a:x.org:xorg-x11-server:::::::: cpe:2.3:a:x.org:xwayland::::::::
Vendors & Products		X.org X.org xorg-x11-server X.org xwayland
References		https://gitlab.freedesktop.org/xorg/xserver/-/commit/ff754b812597177412f2e2fa2b1dd1eecbeb75cf
Metrics		cvssV4_0 `{'score': 6.9, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N'}`