A short sale is always contingent on 3rd party lender approval
... but approval is not automatically guaranteed.

Many buyers search the Charleston MLS and come across listings that look really great because of the seemingly low price compared to similar properties in the same price range.
Is it too good to be true. Sometimes.
If a home ower needs to sell their home and they owe more than the proceeds of the sale will bring and they have no money in order to bring to closing to make up the short fall, the home is generally a short sale contingent on 3rd party lender approval.
Some short sales are approved. Others are not.
Take this example from the agent notes in the Charleston MLS (anonymized for privacy):
DATE >>> SHORT SALE DENIED, NO MORE SHOWINGS <<< DATE
As I wrote a few days ago, The home ATM caused many homeowners to be underwater, buyers who took money out by refinancing when values increased may owe more today than their home is currently worth. And if someone didn't put any money down when buying and then got a home equity line of credit (HELOC) and took that money and spent it on who knows what, if they need to sell today, they are going to be underwater and it will be a short sale.
But the lender doesn't have to just say, OK, we'll approve this and you can go on with your life.
The big problem is for the potential buyer who thinks that they can buy a short sale at a great price, wait endlessly for lender approval only to find out later that they can't buy it.
I'd suggest instead you look at foreclosures or very well priced homes for sale by motivated sellers who aren't upside down on their home.
Photo by my friend Geno Petro from Chicago who has a current fascination with really small cars