Buffer Overread Vulnerability in X.Org X Server and Xwayland
CVE-2026-109903

7.8HIGH

Key Information:

Vendor

X.org

Status
Xwayland
Xorg-x11-server
Vendor
CVE Published:
13 November 2026

What is CVE-2026-109903?

A vulnerability in the X.Org X Server and Xwayland allows for buffer overreads due to improper integer casting. Specifically, when a negative integer is cast to CARD32 in the XvQueryImageAttributes function, it can result in potential crashes for authenticated X clients. This issue affects versions prior to 21.1.26 for X.Org X Server and prior to 24.1.15 for Xwayland, making it critical for users to apply the latest patches to mitigate risks.

Affected Version(s)

xorg-x11-server 0 < 21.1.26

xwayland 0 < 24.1.15

References

https://gitlab.freedesktop.org/xorg/xserver/-/commit/a11d...
patch

CVSS V3.1

Score:
7.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Tristan Madani <TristanInSec@gmail.com>
.