CVEs-PoC/2021/CVE-2021-4037.md

### [CVE-2021-4037](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-4037)
![](https://img.shields.io/static/v1?label=Product&message=Kernel&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=Fixed%20in%20Linux-kernel%20v5.11-rc1%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-284%20-%20Improper%20Access%20Control&color=brightgreen)

### Description

A vulnerability was found in the fs/inode.c:inode_init_owner() function logic of the LInux kernel that allows local users to create files for the XFS file-system with an unintended group ownership and with group execution and SGID permission bits set, in a scenario where a directory is SGID and belongs to a certain group and is writable by a user who is not a member of this group. This can lead to excessive permissions granted in case when they should not. This vulnerability is similar to the previous CVE-2018-13405 and adds the missed fix for the XFS.

### POC

#### Reference
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=01ea173e103e
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0fa3ecd87848

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