The biggest problem that might arise is that the bank won't release the loan until after they have valued the property, any issues arising there and they might refuse funding. The problem you face then it you are contractually obliged to buy it, there's no 'subject to mortgage' clause that allows buyers to walk away from regular sales if issues are discovered after going sale agreed.
If you find yourself in the situation when the lender refuses to fund the purchase, the best you can hope for is only losing the deposit. Worst case, the vendor can keep the deposit and pursue you through the courts for the rest.