Wikileaks has published thousands of documents from the Central Intelligence Agency that expose how US spies can remotely hack and control smartphones, computers, TVs and even vehicles.
One security expert said the leak was so catastrophic that "there are people changing careers - and ending careers - as we speak".
Among the most alarming details in the explosive info dump is that the CIA developed a technology called "Weeping Angel" that can "infest" Samsung smart TVs to transform them into covert microphones.
"After infestation, Weeping Angel places the target TV in 'fake-off' mode, so that the owner believes the TV is off when it is on," Wikileaks writes on its website.
The TV then operates as a bug, allowing spies to record conversations and send them over the internet to a covert CIA server.
Wikileaks also alleges that efforts to infect the vehicle control systems used by modern cars and trucks would allow the CIA to "engage in nearly undetectable assassinations".
The eye-opening expose of the agency's cyber espionage efforts - which includes more than 8700 documents - has been named "Vault 7".
While the authenticity of the documents is yet to be confirmed, WikiLeaks has a long track record of releasing top secret government documents.
Security expert Jake Williams told the Associated Press that it appeared legitimate.
"There's no question that there's a fire drill going on right now," the Rendition InfoSec founder said. "It wouldn't surprise me that there are people changing careers - and ending careers - as we speak."
Bob Ayers, a retired US intelligence official now working as a security analyst, noted that WikiLeaks has promised to release more CIA documents.
"The damage right now is relatively high level," he said. "The potential for really detailed damage will come in the following releases."
TECHNOLOGY COMPROMISES SMARTPHONES
The Wikileaks dump exposes how the CIA's Mobile Devices Branch created technology to infect and control smartphones.
"Infected phones can be instructed to send the CIA the user's geolocation, audio and text communications as well as covertly activate the phone's camera and microphone," Wikileaks reports.
The branch focused its malware on Apple devices because, Wikileaks speculates, iPhones are popular among "social, political, diplomatic and business elites".
The documents show the CIA had a similar unit to target Google's Android phones.
On top of this, the CIA had techniques to bypass the encryption of secretive messaging apps WhatsApp, Signal, Telegram, Wiebo, Confide and Cloackman.
POTENTIAL FOR 'UNDETECTABLE ASSASSINATIONS'
The information dump reveals that the CIA was even investigating ways to take over vehicle controls in modern cars and trucks.
"The purpose of such control is not specified, but it would permit the CIA to engage in nearly undetectable assassinations," Wikileaks writes.
MYSTERY OVER HOW WIKILEAKS OBTAINED DOCUMENTS
It is not clear how WikiLeaks obtained the information.
The publisher said the material came from "an isolated, high-security network situated inside the CIA's Center for Cyber Intelligence in Langley, Virginia".
It didn't say how the files were removed, such as possibly by a rogue employee, by hacking a federal contractor working for the CIA or breaking into a staging server where such hacking tools might be temporarily stored.
The CIA tools, if authentic, could undermine the confidence that consumers have in the safety and security of their computers, mobiles and smart TVs.
WikiLeaks said the data also include details on the agency's efforts to subvert American software products and smartphones, including Apple's iPhone, Google's Android and Microsoft Windows.
WikiLeaks, which has been dropping cryptic hints about the release for a month, said in a lengthy statement that the CIA had "recently" lost control of a massive arsenal of CIA hacking tools as well as associated documentation.
Jonathan Liu, a spokesman for the CIA, said: "We do not comment on the authenticity or content of purported intelligence documents."
If it does prove legitimate, the dump will represent yet another catastrophic breach for the US intelligence community at the hands of WikiLeaks and its allies, which have repeatedly humbled Washington with the mass release of classified material.
One of the purported CIA malware programs is described in the WikiLeaks documents as a "simple DLL hijacking attempt" that had been tested against Microsoft Windows XP, Vista and 7 operating systems.
The technique, which the document called a "Windows FAX DLL injection", introduces computer code that allows an attacker to gain access to a computer process' memory and permissions while at the same time masking the attack.
Williams, who has experience dealing with government hackers, said the voluminous files' extensive references to operation security meant they were almost certainly government-backed.
WikiLeaks said its data also included a "substantial library" of digital espionage techniques borrowed from other countries, including Russia.