Hello Aspirant

It's highly unlikely that having an extra thumb would disqualify you from the CDS medical exam.

The primary focus of the medical examination is to assess your overall physical and mental fitness for the rigors of military training and service. Conditions that would significantly impair your ability to perform your duties are grounds for disqualification.

However, it's crucial to consult with a medical expert or the official CDS medical board for definitive guidance. They can provide specific information based on the latest medical standards and guidelines for the armed forces.