CVE-2023-1829

A use-after-free vulnerability was found in the traffic control index filter (tcindex) in the Linux kernel. The tcindex_delete does not properly deactivate filters, which can later lead to double freeing the structure. This flaw allows a local attacker to cause a use-after-free problem, leading to privilege escalation.

This vulnerability allows local attackers to escalate privileges on affected installations of Canonical Ubuntu. 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 tcindex module. 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 code in the context of the kernel.

A use-after-free vulnerability in the Linux Kernel traffic control index filter (tcindex) can be exploited to achieve local privilege escalation. The tcindex_delete function which does not properly deactivate filters in case of a perfect hashes while deleting the underlying structure which can later lead to double freeing the structure. A local attacker user can use this vulnerability to elevate its privileges to root. We recommend upgrading past commit 8c710f75256bb3cf05ac7b1672c82b92c43f3d28.