Privilege Escalation in MAAS via Websocket Request Manipulation

An Improper Input Validation vulnerability exists in the user websocket handler of MAAS. An authenticated, unprivileged attacker can intercept a user.update websocket request and inject the is_superuser property set to true. The server improperly validates this input, allowing the attacker to self-promote to an administrator role. This results in full administrative control over the MAAS deployment.