cve/2021/CVE-2021-20194.md

### [CVE-2021-20194](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-20194)
![](https://img.shields.io/static/v1?label=Product&message=kernel&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=%3D%20kernel%205.2%20and%20higher.%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-20&color=brighgreen)

### Description

There is a vulnerability in the linux kernel versions higher than 5.2 (if kernel compiled with config params CONFIG_BPF_SYSCALL=y , CONFIG_BPF=y , CONFIG_CGROUPS=y , CONFIG_CGROUP_BPF=y , CONFIG_HARDENED_USERCOPY not set, and BPF hook to getsockopt is registered). As result of BPF execution, the local user can trigger bug in __cgroup_bpf_run_filter_getsockopt() function that can lead to heap overflow (because of non-hardened usercopy). The impact of attack could be deny of service or possibly privileges escalation.

### POC

#### Reference
No PoCs from references.

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