cve/2023/CVE-2023-4623.md

### [CVE-2023-4623](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-4623)
![](https://img.shields.io/static/v1?label=Product&message=Kernel&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=2.6.12%3C%206.6%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: sch_hfsc (HFSC qdisc traffic control) component can be exploited to achieve local privilege escalation.If a class with a link-sharing curve (i.e. with the HFSC_FSC flag set) has a parent without a link-sharing curve, then init_vf() will call vttree_insert() on the parent, but vttree_remove() will be skipped in update_vf(). This leaves a dangling pointer that can cause a use-after-free.We recommend upgrading past commit b3d26c5702c7d6c45456326e56d2ccf3f103e60f.

### POC

#### Reference
- http://packetstormsecurity.com/files/175963/Kernel-Live-Patch-Security-Notice-LSN-0099-1.html

#### Github
No PoCs found on GitHub currently.