The domain-locking implementation in the GARMINAXCONTROL.GarminAxControl_t.1 ActiveX control in npGarmin.dll in the Garmin Communicator Plug-In 2.6.4.0 does not properly enforce the restrictions that (1) download and (2) upload requests come from a web site specified by the user, which allows remote attackers to obtain sensitive information or reconfigure Garmin GPS devices via unspecified vectors related to a "synchronisation error."