When an actor tries to access a resource or carry out an action, the software
doesn't do an authorisation check.
Assuming a user with a given identity, authorization is the process of
determining whether that user can access a given resource, based on the user's
privileges and any permissions or other access-control specifications that
apply to the resource. When access control checks are not applied, users are
able to access data or perform actions that they should not be allowed to
perform. This can lead to a wide range of problems, including information
exposures, denial of service, and arbitrary code execution.