### [CVE-2019-3842](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-3842)
![](https://img.shields.io/static/v1?label=Product&message=systemd&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=n%2Fa&color=blue)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-285&color=brighgreen)

### Description

In systemd before v242-rc4, it was discovered that pam_systemd does not properly sanitize the environment before using the XDG_SEAT variable. It is possible for an attacker, in some particular configurations, to set a XDG_SEAT environment variable which allows for commands to be checked against polkit policies using the "allow_active" element rather than "allow_any".

### POC

#### Reference
- http://packetstormsecurity.com/files/152610/systemd-Seat-Verification-Active-Session-Spoofing.html
- https://www.exploit-db.com/exploits/46743/

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