A flaw in the X Keyboard Extension of the Xorg X11 server allocates key name memory with an insufficient buffer size for the maximum supported range, allowing an authenticated local client to send requests that modify the keycode range and trigger a heap-based buffer overflow. This vulnerability can lead to arbitrary code execution or a denial of service by crashing the X server.

The affected product is the Xorg X11 server. Specific vendor and version details are not enumerated in the provided data, but the issue applies to Linux/Unix environments running the Xorg server that support XKB functionality.

The CVSS score of 7.8 reflects a high risk for local attackers who can authenticate to the X server. With the EPSS score unavailable, the potential for exploitation remains uncertain, and the vulnerability is not listed in CISA’s KEV catalog. The likely attack vector is a local authenticated client issuing XKB ChangeKeycodeRange requests, which can destabilize the X server or give the attacker code execution capabilities on the host system.