Advisory Details

October 29th, 2025

X.Org Server XkbSetCompatMap Numeric Truncation Error Privilege Escalation Vulnerability

ZDI-25-975
ZDI-CAN-27560

CVE ID CVE-2025-62231
CVSS SCORE 7.8, AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
AFFECTED VENDORS X.Org
AFFECTED PRODUCTS Server
VULNERABILITY DETAILS

This vulnerability allows local attackers to escalate privileges on affected installations of X.Org Server. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the handling of XkbSetCompatMap requests. The issue results from the lack of proper validation of user-supplied data, which can result in an integer truncation before allocating a buffer. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of root.

ADDITIONAL DETAILS X.Org has issued an update to correct this vulnerability. More details can be found at:
https://lists.x.org/archives/xorg-announce/2025-October/003635.html
DISCLOSURE TIMELINE
  • 2025-08-21 - Vulnerability reported to vendor
  • 2025-10-29 - Coordinated public release of advisory
  • 2025-10-29 - Advisory Updated
CREDIT Jan-Niklas Sohn
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