cve/2021/CVE-2021-33033.md

### [CVE-2021-33033](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-33033)
![](https://img.shields.io/static/v1?label=Product&message=n%2Fa&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=n%2Fa&color=blue)
![](https://img.shields.io/static/v1?label=Vulnerability&message=n%2Fa&color=brighgreen)

### Description

The Linux kernel before 5.11.14 has a use-after-free in cipso_v4_genopt in net/ipv4/cipso_ipv4.c because the CIPSO and CALIPSO refcounting for the DOI definitions is mishandled, aka CID-ad5d07f4a9cd. This leads to writing an arbitrary value.

### POC

#### Reference
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.14
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.7
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1165affd484889d4986cf3b724318935a0b120d8
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ad5d07f4a9cd671233ae20983848874731102c08

#### Github
- https://github.com/ARPSyndicate/cvemon