According to your description, the CPU voltages mentioned are expected, please note the following;
Note that the maximum is 1.52V and your report is 1.42V, this means that your chip is not defective; on the contrary, it is behaving as expected.
For further reference see 6th Generation Intel® Core™ Processor Family Datasheet, Vol. 1, Table 7-2.
Thank you for joining the Processors Community.
In regard to your inquiry I just wanted to let you know that Intel does not support overclocking due to the possible issues that might happen when you overclock the processor, we recommend using the processor at stock configurations; however, if you need to gather some information about overclocking I would recommend posting your inquiry in places like; Forums, Overclockers Forums in order to obtain more feedback from peers.