The only NSA reform amendment to pass either congressional chamber since 2013's mass spying revelations became public has reportedly been cut from the "Cromnibus" spending bill that is currently under consideration in the final days of Congress' lame-duck session, according to U.S. News & World Report.

The Lofgren-Massie amendment passed in June with a vote of 293-123, and would limit the NSA's ability to spy on Americans' communications data, but many in-the-know are saying that the privacy reforms have been dropped from the bill altogether.

While the public is not yet privy to the content of the 11 spending bills, known as Cromnibus, as they are still being negotiated by the House and Senate appropriations committees, Peter Whippy, a spokesman for amendment co-sponsor Rep. Zoe Lofgren, said the NSA reform measures are "not included in the Cromnibus," according to U.S. News & World Report.

The contents of the bill are expected to be released next week, reported the Wall Street Journal.

Cato Institute policy analyst Patrick Eddington said reliable sources informed him Wednesday that congressional leadership plans to remove the privacy language.

Following the disclosure that the NSA privacy provision would likely be omitted from the spending bill, 30 civil-liberties groups sent an open letter to House leadership asking for its reconsideration.

"Failing to include this amendment in the forthcoming FY15 omnibus will send a clear message to Americans that Congress does not care if the NSA searches their stored communications or if the government pressures American technology companies to build vulnerabilities into their products that assist in NSA surveillance," the letter read.

Signatories include the Electronic Frontier Foundation, Libertarian Party and the Sunlight Foundation.

On Thursday, U.S. Sen. Ron Wyden, D-Ore., introduced a new measure, dubbed the Secure Data Act, to prevent the government from building backdoors or security vulnerabilities into U.S. software and electronics, such as computers or cellphones. Lofgren is spearheading the effort in the House, reported the National Journal.

"Strong encryption and sound computer security is the best way to keep Americans' data safe from hackers and foreign threats. It is the best way to protect our constitutional rights at a time when a person's whole life can often be found on his or her smartphone. And strong computer security can rebuild consumer trust that has been shaken by years of misstatements by intelligence agencies about mass surveillance of Americans," Wyden said. "This bill sends a message to leaders of those agencies to stop recklessly pushing for new ways to vacuum up Americans' private information, and instead put that effort into rebuilding public trust."