The X.Org X server, an open-source implementation of the X Window System, contains several security flaws in its xorg-x11-server component. These include CVE-2026-33999 (denial of service via integer underflow in XKB compatibility map handling), CVE-2026-34000 (information disclosure and denial of service via out-of-bounds read in XKB geometry processing), CVE-2026-34001 (use-after-free vulnerability causing server crash and potential memory corruption), CVE-2026-34002 (information disclosure or denial of service via out-of-bounds read in XKB modifier map handling), and CVE-2026-34003 (information exposure and denial of service via out-of-bounds memory access). These vulnerabilities affect multiple architectures and variants of Red Hat Enterprise Linux 9.6 Extended Update Support and related CodeReady Linux Builder products. Red Hat has released security updates to address these issues as detailed in advisory RHSA-2026:20558.

Successful exploitation of these vulnerabilities could lead to denial of service conditions causing the X.Org X server to crash or become unresponsive. Some vulnerabilities also allow information disclosure through out-of-bounds memory reads. The use-after-free flaw could potentially cause memory corruption, which might be leveraged for further impact. These issues affect the graphical server component, potentially disrupting graphical user interfaces on affected systems.

Red Hat has released security updates for the xorg-x11-server package in Red Hat Enterprise Linux 9.6 Extended Update Support and related products. Applying these official updates will remediate the vulnerabilities described. Users should follow Red Hat's guidance at https://access.redhat.com/articles/11258 to update affected packages promptly. No additional mitigation actions are specified or required beyond applying the vendor-provided patches.