X.Org Server RecalculateMasterButtons Out-Of-Bounds Access Local Privilege Escalation Vulnerability

January 4th, 2024
ZDI-24-011 ZDI-CAN-22412

CVE ID

CVE-2023-6377

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 Button Action objects. The issue results from the lack of proper validation of user-supplied data, which can result in a memory access past the end of an allocated 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/2023-December/003435.html

Disclosure Timeline

  • 2023-11-15 - Vulnerability reported to vendor
  • 2024-01-04 - Coordinated public release of advisory
  • 2024-07-01 - Advisory Updated

Credit

Jan-Niklas Sohn

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