Ten years ago, hackers would hand knowledge of such flaws to Microsoft and Google free, in exchange for a T-shirt or perhaps for an honorable mention on a company’s Web site. Even today, so-called patriotic hackers in China regularly hand over the information to the government.

Now, the market for information about computer vulnerabilities has turned into a gold rush. Disclosures by Edward J. Snowden, the former N.S.A. consultant who leaked classified documents, made it clear that the United States is among the buyers of programming flaws. But it is hardly alone.

Israel, Britain, Russia, India and Brazil are some of the biggest spenders. North Korea is in the market, as are some Middle Eastern intelligence services. Countries in the Asian Pacific, including Malaysia and Singapore, are buying, too, according to the Center for Strategic and International Studies in Washington.

To connect sellers and buyers, dozens of well-connected brokers now market information on the flaws in exchange for a 15 percent cut. Some hackers get a deal collecting royalty fees for every month their flaw is not discovered, according to several people involved in the market.