A flaw was found in X.Org server. In the XISendDeviceHierarchyEvent function, it is possible to exceed the allocated array length when certain new device IDs are added to the xXIHierarchyInfo struct. This can trigger a heap buffer overflow condition, which may lead to an application crash or remote code execution in SSH X11 forwarding environments.
CVE-2024-21885
CVSS base score
7.8 (v3.1)
Severity
HIGH
Attack vector
Local
Weakness
CWE-122
Last modified
November 4, 2026
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H