The Local HTTP API in Radio Thermostat CT50 and CT80 1.04.84 and below products allows unauthorized access via a DNS rebinding attack. This can result in remote device temperature control, as demonstrated by a tstat t_heat request that accesses a device purchased in the Spring of 2018, and sets a home's target temperature to 95 degrees Fahrenheit. This vulnerability might be described as an addendum to CVE-2013-4860.