CVE-2020-14361: X.Org Server XkbSelectEvents Integer Underflow Privilege Escalation Vulnerability

A flaw was found in X.Org Server. An Integer underflow leading to heap-buffer overflow was found in XkbSelectEvent may lead to a privilege escalation vulnerability.

— Red Hat

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 XkbSelectEvents requests. The issue results from the lack of proper validation of user-supplied data, which can result in an integer underflow before writing to memory. An attacker can leverage this vulnerability to escalate privileges and execute code in the context of root.

— ZDI

X.Org server could allow a local authenticated attacker to gain elevated privileges on the system, caused by an integer underflow in XkbSelectEvents. By sending a specially-crafted request, an authenticated attacker could exploit this vulnerability to gain elevated privileges.

— IBM