CVE-2026-93518

A flaw was found in xorg-x11-server. Due to an integer truncation issue during memory allocation calculations within the X Keyboard Extension (XKB), the server allocates an undersized buffer when resizing key types. An authenticated local client can exploit this vulnerability by sending specially crafted XKB requests, causing a heap-based buffer overflow. This can result in arbitrary code execution or a denial of service (DoS).

Red Hat has evaluated this vulnerability as Moderate impact because exploitation requires an established, authenticated connection from a local client to the display server. While triggering the integer truncation during keyboard mapping reconfiguration can result in memory corruption or service termination, access is constrained to interactive user sessions. Headless server deployments that do not run graphical display services such as Xorg or Xwayland are not exposed to this risk.

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.