An insecure direct object reference (IDOR) vulnerability in the Fullstep V5 registration process allows authenticated users to access data belonging to other registered users through various vulnerable authenticated resources in the application. The vulnerable endpoints result from: '/api/suppliers/v1/suppliers//false' to list user information; and '/#/supplier-registration/supplier-registration//2' to update your user information (personal details, documents, etc.).
The vulnerability has been fixed by the Fullstep team in version 5.30.07, which has been available in production since January 29, 2026.