An undercover TSA inspector with an improvised explosive device stuffed in his pants got past two security screenings at Newark Airport — including a pat-down — and was cleared to get on board a commercial flight, sources told The Post yesterday.

The breach took place Feb. 25, when the Transportation Security Administration’s special operations team — the agency’s version of internal affairs — staged a mock intrusion at the airport.

“This episode once again demonstrates how Newark Airport is the Ground Zero of TSA failures,” a source said.

The “bomber” was part of the four-person “Red Team” that posed as ticketed passengers and filed through the B1 checkpoint of Terminal B — home of American Airlines, JetBlue and Delta, sources said.