There is a possibility that the Russian government, through hackers, may have interfered with the US election, by which hacking into a DNC email server and then leaking the information to Wikileaks while also having hacked into an RNC email server and sitting on that information. This begs two questions, why would Putin and the Russian government want Trump as president, and does this compromise Trump and his administration from a security standpoint.
The first question is relatively simple to answer. It is in the best interest of Putin and Russia if the US has a weak leader. This would allow Putin to have almost free reign in Eastern Europe with little hindrance from the US and by extension NATO. For example, a strong US president would more than likely not only complain about a Russian incursion into the Ukraine, but likely do something about it either by sending arms or advisors or convincing NATO allies that it's a bad idea to let the Russians do this. On the other hand a weak US president is likely to cave in, to appease the Russians. Thus the Russians would likely want to tip the US election towards someone they think would be weak or at the very least easily manipulated. Given Trumps propensity to Twitter tantrums with pretty much anyone he takes offense from, he is at the least very easy to manipulate. An old KGP pro like Putin is probably giddy like a school girl at the prospect of someone that malleable in the oval office.
Which brings up the second question. What does this mean for US security? To answer this it is useful to look at how spy agencies compromise people on the other side. It's a simple formula really, find someone who has access to what you want to know, befriend them, provide them with something they don't have but want, (sex, money, power), get some compromising information on them then blackmail them into providing you with what you want.
Now if what the reports of what the CIA is saying is true, this is almost a classic cold war compromise of an asset. Help was provided; information that can harm the asset has been secured. Now all that is needed is for the time to use that to compromise the asset, in this case President of the United States Donald Trump. Now Putin isn't likely to be asking Trump to sneak state secrets out of the White House to be dropped by the third lamp post along Pennsylvania Avenue as it's just as likely that Trump will Tweet the secrets out in a pique of ego. Where the compromise will be most useful is when Putin decides to invade the Ukraine or the Baltic states to reform the former glory that was the Soviet Union. Between planting false stories in fake news sites designed to make Trump feel that the leaders of the countries Putin wants to control have said nasty things about Trump; and then threatening to release the damaging information the intelligence services of the Russian Federation now hold; Trump will be made to at the least do nothing about, if not cheer for Russian tanks roaming the streets of Kiev and Riga.
If any of this were true for someone working in an area with security sensitive information, even if they weren't passing secrets, they would be considered compromised and reassigned to somewhere they could do no harm. That's a little difficult when the compromised asset is the President of the United States. There's a good chance that this is a Russian attempt to destabilize NATO and prevent US influence in Europe allowing Putin to assert Russian influence in the region. If these revelations are true, we may be seeing the greatest intelligence coup since Operation Bodyguard.