CVE-2026-34000: Red Hat Enterprise Linux

Critical severity, CVSS 9.1. EPSS: 0.5% chance of exploitation in the next 30 days.

A flaw was found in the X.Org X server. This out-of-bounds read vulnerability in the XKB geometry processing, specifically within the `CheckSetGeom()` and `XkbAddGeomKeyAlias` functions, allows an attacker to read uninitialized or out-of-bounds memory. An attacker with a connection to the X11 server, either locally or remotely, can exploit this without user interaction. This could lead to the disclosure of memory contents or cause a denial of service by crashing the server.

Affected products

• Red Hat Enterprise Linux: version 6.0 only; version 7.0 only; version 8.0 only; version 9.0 only; version 10.0 only
• X.org X Server: affected versions not specified

Published 2026-05-05. Last modified 2026-06-17.