Authorization regression testing is repeated validation that access-control rules still work after code changes, refactors, or new features. It checks that users can only read, modify, or act on resources they are actually allowed to use, even when routes, object identifiers, roles, or workflow states change. The goal is to catch broken object-level authorization before attackers do.
This matters because authorization bugs often reappear quietly. A fix may protect one endpoint, but a later update can reopen the same weakness in a new path, API version, or admin tool. In real attacks, this is how IDOR and broken access control issues spread: a request reaches a record or action without a server-side ownership check. Defenders use regression tests to replay those access patterns with different user roles and objects, confirming that every read and state change is denied unless explicitly allowed. Strong regression coverage turns authorization from a one-time patch into a durable control.