A pre-auth command injection vulnerability in the warn-proceed handler of Sophos Web Appliance older than version 4.3.10.4 allows execution of arbitrary code.
https://www.sophos.com/en-us/security-advisories/sophos-sa-20230404-swa-rce
http://packetstormsecurity.com/files/172016/Sophos-Web-Appliance-4.3.10.4-Command-Injection.html