CVE-2023-0494 entails local privilege elevation on systems where the X.Org Server is privileged and remote code execution is supported for SSH X forwarding sessions. Thankfully for many modern X.Org Server environments these days, the X.Org Server is no longer run as root / elevated privileges but for older systems and in other select configurations unfortunately remains running in such a vulnerable configuration.
The CVE-2023-0494 vulnerability involves a use-after-free condition within DeepCopyPointerClasses for allowing reading and writing to freed memory via ProcXkbSetDeviceInfo() and ProcXkbGetDeviceInfo().