Citrix NetScaler SD-WAN devices through v9.1.2.26.561201 allow remote attackers to execute arbitrary shell commands as root via a CGISESSID cookie. On CloudBridge (the former name of NetScaler SD-WAN) devices, the cookie name was CAKEPHP rather than CGISESSID.
https://www.exploit-db.com/exploits/42346/
https://www.exploit-db.com/exploits/42345/
https://support.citrix.com/article/CTX225990