### [CVE-2024-39274](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-39274)
![](https://img.shields.io/static/v1?label=Product&message=Mattermost&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=9.10.0%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=9.5.0%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=9.5.7%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=9.7.0%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=9.7.6%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=9.8.0%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=9.8.2%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=9.9.0%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=9.9.1%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-284%3A%20Improper%20Access%20Control&color=brightgreen)

### Description

Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5 and 9.8.x <= 9.8.1 fail to properly validate that the channel that comes from the sync message is a shared channel, when shared channels are enabled, which allows a malicious remote to add users to arbitrary teams and channels

### POC

#### Reference
- https://mattermost.com/security-updates

#### Github
- https://github.com/fkie-cad/nvd-json-data-feeds