cve/2023/CVE-2023-4208.md

### [CVE-2023-4208](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-4208)
![](https://img.shields.io/static/v1?label=Product&message=Kernel&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=3.18%3C%206.5%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-416%20Use%20After%20Free&color=brighgreen)

### Description

A use-after-free vulnerability in the Linux kernel's net/sched: cls_u32 component can be exploited to achieve local privilege escalation.When u32_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 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81.

### POC

#### Reference
No PoCs from references.

#### Github
- https://github.com/hshivhare67/Kernel_4.1.15_CVE-2023-4206_CVE-2023-4207_CVE-2023-4208
- https://github.com/nomi-sec/PoC-in-GitHub