A mass assignment vulnerability exists in the /api/invite/:code endpoint of the mintplex-labs/anything-llm repository, allowing unauthorized creation of high-privileged accounts. By intercepting and modifying the HTTP request during the account creation process via an invitation link, an attacker can add a role property with admin value, thereby gaining administrative access. This issue arises due to the lack of property allowlisting and blocklisting, enabling the attacker to exploit the system and perform actions as an administrator.