Cumming’s 41st-minute effort had doubled the visitors’ advantage after Paul Hanlon opened the scoring on 25 minutes.
Jon Robertson then grabbed a lifeline for the Cowdenbeath to set up a grandstand finish the leagues bottom side, but Hibs held on for the win to ensure they remained in the pursuit of runaway leaders Hearts.
Having enjoyed an early period of dominance, Hibs broke the deadlock midway through the first half. Scott Allan delivered the ball into the Cowdenbeath area and Hanlon was on the end to guide a left-footed shot past the hapless Robbie Thomson.
And Hibs would see themselves go into the break with their lead double. David Gray’s whipped delivery found Cummings in the box and he lashed a shot into the bottom-left corner of the goal to reward Hibs for their early dominance in the game.
The second half produced much of the same, with Hibs camped outside the Cowdenbeath area in search of further goals – with Cummings, in particular, thwarted on a number of occasions from extending his sides lead further.
And they hosts took advantage of their spirited defending by grasping an opportunity to get back into the game midway through the second period.
Robertson was found in the Hibs box by Lewis Milne’s and the striker nodded past half-time replacement Perntreou in the Hibs goals to give his side a chance to claim a much-needed point.