WASHINGTON—WikiLeaks released a massive trove of documents and files Tuesday that it says exposes how the Central Intelligence Agency hacks smartphones, computer operating systems, message applications and internet-connected televisions, in what would be one of the biggest breaches in the spy agency’s history.

The group, which was behind the leak of emails stolen from the Democratic National Committee during last year’s presidential campaign, said the release consists of 8,761 documents and files from the CIA’s Center for...