CVE-2026-50262

An out-of-bounds read flaw was found in the X.Org X server and Xwayland in __glXDisp_ChangeDrawableAttributes(). A wrong size validation check can read a client-controlled number of bytes, exceeding the request buffer, leading to information disclosure. A write path also exists but requires byte-swapped clients which is disabled by default.

Red Hat rates this issue as Moderate impact. In xorg-x11-server and xorg-x11-server-Xwayland, __glXDisp_ChangeDrawableAttributes() validates request size incorrectly, allowing a local X client to read bytes beyond the GLX request buffer—information disclosure. An out-of-bounds write path also exists but requires byte-swapped clients, which is disabled by default on Red Hat builds. Any local user who can connect to the X server display can trigger the read path. Upstream fixed this in xorg-server 21.1.23 and xwayland 24.1.12.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.