CVE-2023-4207 Information

Description

A use-after-free vulnerability in the Linux kernel’s net/sched: cls_fw component can be exploited to achieve local privilege escalation.

When fw_change() is called on an existing filter the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class as tcf_unbind_filter() is always called on the old instance in the success path decreasing filter_cnt of the still referenced class and allowing it to be deleted leading to a use-after-free.

We recommend upgrading past commit 76e42ae831991c828cffa8c37736ebfb831ad5ec.

Reference

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=76e42ae831991c828cffa8c37736ebfb831ad5ec https://kernel.dance/76e42ae831991c828cffa8c37736ebfb831ad5ec