A vulnerability has been patched in Starlette, a Python library for developing web services used by products like FastAPI. An unauthenticated attacker can exploit this vulnerability to bypass authentication and access protected URL paths. The vulnerability is caused by insufficient verification of the path in the Host header. This allows unauthorized access to functionalities or data of web services using vulnerable Starlette versions. The impact depends on the type of data processed and functionalities provided by the vulnerable web service.