In Apache Traffic Control Traffic Ops prior to 6.1.0 or 5.1.6, an unprivileged user who can reach Traffic Ops over HTTPS can send a specially-crafted POST request to /user/login/oauth to scan a port of a server that Traffic Ops can reach.
When ORT (now via atstccfg) generates ip_allow.config files in Apache Traffic Control 3.0.0 to 3.1.0 and 4.0.0 to 4.1.0, those files include permissions that allow bad actors to push arbitrary content into and remove arbitrary content from CDN cache servers. Additionally, these permissions are potentially extended to IP addresses outside the desired range, resulting in them being granted to clients possibly outside the CDN arcitechture.