A reference leak vulnerability exists in the items-view union and subtraction operators of aio-libs/multidict versions 6.7.0 through 6.9.0. This flaw allows a remote client to cause unbounded memory growth by leaking key-identity and value objects during certain set operations on dictionary views. The leak occurs because new references are created but not properly released in specific code paths. This issue can cause server processes using these versions to consume increasing amounts of memory until termination.