The X11 Xorg server contains a buffer overflow in the XFixes pointer barrier event handling. When an authenticated client configures more pointer barriers than the internal buffer can hold and then moves the cursor, the server writes beyond the buffer boundaries. If an attacker controls the overflow contents, they can execute arbitrary code or cause the server to terminate, leading to a denial of service.

The vulnerability affects the X.Org X11 server. No specific version information is listed, so all installed instances of xorg-x11-server that accept pointer barrier configurations are potentially vulnerable.

The CVSS score of 7.8 indicates a high severity level. The EPSS is not available, and the CISA KEV catalog, suggesting that publicly known exploits have not yet been observed. Because the flaw requires an authenticated client to manipulate pointer barriers, the attack surface is limited to trusted clients or local users with access to the server.