In order to jailbreak IOS 4.2.6 on your Verizon iPhone 4 via Greenpois0n RC5.4 (MAC OS X), follow the below instructions:
STEP#1: First of all launch GreenPois0n RC5 and connect your iDevice into your Mac via a USB cable and hit Jailbreak:
STEP#2: Now follow the on-screen guidelines to direct your iDevice into DFU mode.
Once Greenpois0n is done with its job, Cydia will be installed on your Verizon iPhone 4!!!!