CVE-2026-29782: OpenSTAManager Affected by Remote Code Execution via Insecure Deserialization in OAuth2

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.