OpenSTAManager is an open source management software for technical assistance and invoicing. Prior to version 2.10.2, the oauth2.php file in OpenSTAManager is an unauthenticated endpoint ($skip_permissions = true). It loads a record from the zz_oauth2 table using the attacker-controlled GET parameter state, and during the OAuth2 configuration flow calls unserialize() on the access_token field without any class restriction. This issue has been patched in version 2.10.2.
CWE-502