X.Org Server XkbCopyNames Double Free Local Privilege Escalation Vulnerability

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 XkbCopyNames requests. The issue results from the lack of validating the existence of an object prior to performing further free operations on the object. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of root.

Additional Details

https://lists.x.org/archives/xorg-announce/2022-December/003302.html
https://bugzilla.redhat.com/show_bug.cgi?id=2151761

Disclosure Timeline

• 2022-12-02 - Vulnerability reported to vendor
• 2022-12-28 - Coordinated public release of advisory
• 2023-12-04 - Advisory Updated

Credit

Jan-Niklas Sohn

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