A circuit to protect a USB connector from corrosion on its CC pins includes a first node coupled to a first power source or a first pull-down resistor, a second node coupled to the CC pins and a second power source, and a second pull-down resister coupled to the second node. A detection circuit compares the voltage at the first node with a first reference voltage. The detection circuit also compares the voltage at the second node with second and third reference voltages. A control logic circuit generates a corrosion detection signal in response to the voltage at the second node being less than the third reference voltage and greater than the second reference voltage when the voltage at the first node is greater than the first reference voltage.