ESC are normally rated by amps. As long as you do not exceed the amount it is rated for the "magic smoke"
will not escape.
The concern is going to be the extra voltage to the motors. INITIALLY, the motors will hold up to the additional voltage. However, it is going to shorten the life of the motor - how much is hard to say.
Perhaps someone with more experience with electrics can tell you how much the motor life will be shortened.