Creepers have approximately 1.5 - 2x detonation range. Meaning they will start to detonate at the players sword range limit.

It is VERY hard to kill creepers now without a bow. Usually the range of a creeper is half the swords range; how far you can hit an enemy.

For example, a player standing still in the middle of a single block can hit an enemy 2 blocks away from the player from any side. Now that this bug effects creepers, creepers will detonate 4-5 blocks away from the player making it hard to kill the creep. Normally creepers would start to detonate at 2-3 blocks away from player.