The vulnerability stems from missing CSRF protections (POST method requirements) and insufficient permission checks in form validation endpoints. The patches consistently add @POST annotations and credential permission checks (checkPermissionToAccessCredentials) to various doFill* and doCheck* methods across multiple components. These methods handle credential selection and connection validation, and their pre-patch versions allowed: 1) GET-based requests vulnerable to CSRF, and 2) credential enumeration/usage without proper authorization. The modified functions directly correspond to the attack surface described in CVE-2023-23847 where attackers could manipulate credential IDs through forged requests.