The fireball projectiles that blazes and ghasts fire can be used to light campfires, even when /gamerule mobGriefing is set to false. Interestingly, ghast fireballs can only light campfires when mobGriefing is false, as the campfire is destroyed otherwise.

I suspect the blaze's ability to light campfires comes from MC-159947 being fixed, as fire charges and blazes use the same projectile (small_fireball).