A JSON Injection vulnerability exists in the mintplex-labs/anything-llm application, specifically within the username parameter during the login process at the /api/request-token endpoint. The vulnerability arises from improper handling of values, allowing attackers to perform brute force attacks without prior knowledge of the username. Once the password is known, attackers can conduct blind attacks to ascertain the full username, significantly compromising system security.
The product does not properly handle when the expected number of values for parameters, fields, or arguments is not provided in input, or if those values are undefined.