Surely you jest. Have you read the article?
"More than 100 suspected terrorists have been sent by the CIA into the covert system, according to current and former U.S. intelligence officials and foreign sources. This figure, a rough estimate based on information from sources who said their knowledge of the numbers was incomplete, does not include prisoners picked up in Iraq. The detainees break down roughly into two classes, the sources said."
"About 30 are considered major terrorism suspects and have been held under the highest level of secrecy at black sites financed by the CIA and managed by agency personnel, including those in Eastern Europe and elsewhere, according to current and former intelligence officers and two other U.S. government officials. Two locations in this category -- in Thailand and on the grounds of the military prison at Guantanamo Bay -- were closed in 2003 and 2004, respectively."
"A second tier -- which these sources believe includes more than 70 detainees -- is a group considered less important, with less direct involvement in terrorism and having limited intelligence value. These prisoners, some of whom were originally taken to black sites, are delivered to intelligence services in Egypt, Jordan, Morocco, Afghanistan and other countries, a process sometimes known as "rendition." While the first-tier black sites are run by CIA officers, the jails in these countries are operated by the host nations, with CIA financial assistance and, sometimes, direction."
There is no way we are going to let the 1st tier go and the 2nd tier prisoners are returned to their native countries through rendition.
I don't think this is the result of a leak.
How else did this classified information become public? In the article, it is mentioned that, "The CIA has been hiding and interrogating some of its most important al Qaeda captives at a Soviet-era compound in Eastern Europe, according to U.S. and foreign officials familiar with the arrangement. Also, "The Washington Post is not publishing the names of the Eastern European countries involved in the covert program, at the request of senior U.S. officials. They argued that the disclosure might disrupt counterterrorism efforts in those countries and elsewhere and could make them targets of possible terrorist retaliation."