The Mobile and Remote Access (MRA) endpoint-validation feature in Cisco TelePresence Video Communication Server (VCS) Expressway X8.5.2 improperly validates the phone line used for registration, which allows remote authenticated users to conduct impersonation attacks via a crafted registration, aka Bug ID CSCuv40396.
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.