A shell escape vulnerability in /webconsole/APIController in the API Configuration component of Sophos XG firewall 17.0.8 MR-8 allows remote attackers to execute arbitrary OS commands via shell metachracters in the "X-Forwarded-for" HTTP header.
https://www.sophos.com/en-us/legal/sophos-responsible-disclosure-policy.aspx
https://github.com/klsecservices/Advisories/blob/master/KL-SOPHOS-2018-003.md