The basic principle is that a person can conclude whatever contracts he wants with his free and sound will, but if the will is marred by a defect, then the contract is voidable for the benefit of the contractor whose defect has occurred.
And the Vices of Consent that the Syrian Civil Law adopted are:
Mistake – Coercion- Fraud – Inequity.
It is not part of the general system, as it must be raised by the concerned person before the judiciary until it is decided to nullify it by the court