Apparently the NSA bought VUPEN’s services on September 14, 2012. The NSA contract is for a one-year subscription to the company’s “binary analysis and exploits service”. VUPEN is one of a handful of companies that sell software exploits and vulnerability details. The company, based in Montpellier, France, employs a number of security researchers who do original vulnerability research and develop exploits for bugs that they find.
This information is then sold to governments and law enforcement agencies. VUPEN has promised that the company only will sell its services to NATO countries and will not deal with oppressive regimes. However there are concerns that VUPEN does not actually help anyone with this service, and simply allows governments to create malware.
In an ideal world, the NSA would buy the exploit and then pass it on to Microsoft or the hardware makers to fix.