Social Security Trustees report that social security will be able to make full payments until 2037(pdf). Tax receipts will dip below outlays before then, but this is precisely why the Social Security program has taken in more money than it needed, so that it could handle baby boomer retirement and increased life spans.
Any projection which goes out 27 years is so incredibly reliant on the embedded assumptions about growth, employment and lifespans that it amounts to a fiction. It is, at best, a guess.
Increase growth by just a little bit and the entire "problem" goes away. Get rid of the taxation cap so the rich are not capped in what they pay and the entire problem goes away. Assume higher employment, and the entire problem goes away. Assume a reduction in inequality, and the problem goes away.
The US has a number of problems which are at or near crisis, such as employment, inequality and healthcare costs, to name just a few. Social Security is not one of them. It isn't even close, and politicians and billionaires like Pete Peterson who are trying to gin up a crisis should be ashamed of themselves.
If they want the US budget more in order they should look at health care, where single payer could cut costs by at least a third, and at the military, where real spending has doubled since the end of the Clinton administration.
Or they should work on increasing employment and increasing wages for ordinary people. That's a crisis.
Instead of dealing with real problems, instead of tackling the medical industry or the military-industrial complex, instead of fixing the job situation, they want to steal money from old people.