OpenAEV is an open source platform allowing organizations to plan, schedule and conduct cyber adversary simulation campaign and tests. Starting in version 1.11.0 and prior to version 2.0.13, the /api/reset endpoint behaves differently depending on whether the supplied username exists in the system. When a non-existent email is provided in the login parameter, the endpoint returns an HTTP 400 response (Bad Request). When a valid email is supplied, the endpoint responds with HTTP 200. This difference in server responses creates an observable discrepancy that allows an attacker to reliably determine which emails are registered in the application. By automating requests with a list of possible email addresses, an attacker can quickly build a list of valid accounts without any authentication. The endpoint should return a consistent response regardless of whether the username exists in order to prevent account enumeration. Version 2.0.13 fixes this issue.