Improper access control arbitrary allows account creation
June 9, 2025

Products Impacted
This vulnerability is present in all versions of BackendAI. We tested on version 25.3.3 (commit f7f8fe33ea0230090f1d0e5a936ef8edd8cf9959).
CVSS Score: 9.8
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE Categorization
CWE-284: Improper Access Control
Details
To sign up, an attacker can use the API endpoint /func/auth/signup. Then, using the login credentials, the attacker can access the account.
To reproduce this, we made a Python script to reach the endpoint and signup. Using those login credentials on the endpoint /server/login we get a valid session. When running the exploit, we get a valid AIOHTTP_SESSION cookie, or we can reuse the credentials to log in.

We can then try to login with those credentials and notice that we successfully logged in

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