This vulnerability (CVE-2026-56000) affects the X.Org xorg-x11-server and xwayland components. It is a heap use-after-free issue caused by the CommonMakeCurrent() function referencing potentially reallocated memory. Local attackers with an X connection capable of providing GLX commit commands to the affected X server versions prior to 21.2.24 (xorg-server) and 24.1.13 (xwayland) can exploit this flaw. The CVSS 4.0 base score is 9.0, indicating critical severity with network attack vector but requiring low privileges and high complexity. The vulnerability impacts confidentiality, integrity, availability, and security requirements highly. No official patch or remediation level is currently provided in the available data.

Successful exploitation of this heap use-after-free vulnerability could allow local attackers with X connection access to cause memory corruption, potentially leading to denial of service or arbitrary code execution within the X server process. The vulnerability affects confidentiality, integrity, and availability with high impact as indicated by the CVSS score of 9.0.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, restrict local access to the X server and limit untrusted GLX commits. Monitor vendor channels for updates and apply patches promptly once available.