Sam Baldock’s well-taken 50th-minute goal had looked set to hand the Dons their third straight home win but Corr poked in two minutes into injury-time to rescue a draw.
Exeter held their own in a fiery first-half and Ryan Harley was unlucky not to put them ahead when his 18-yard shot cannoned back off the post before keeper Willy Gueret brilliantly denied Marcus Stewart from the rebound.
The Dons upped the tempo after the break and Baldock scored his ninth goal of the season to break the deadlock.
The pacy striker played a neat one-two with Aaron Wilbraham before smashing a right-foot piledriver into the roof of the net from 10 yards.
But Exeter piled forward late on and substitute Corr prodded in Adam Stansfield’s cross from close range at the death to earn the Grecians a point.