CVE-2026-50262: Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: out-of-bounds read/write in glx changedrawableattributes

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-05 · updated 2026-08-05
Weakness: CWE-125

Description

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.

Affected products

Red Hat Enterprise Linux: 7.0, 8.0, 9.0, 10.0
xorg-x11-server: before 21.1.23 — fixed in 21.1.23
X.Org xwayland: before 24.1.12 — fixed in 24.1.12

How to fix

Upgrade to a fixed version: xorg-x11-server 21.1.23; X.Org xwayland 24.1.12. Check the vendor advisory for mitigations.

References

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