The son of former 'RHOC' star Lauri Peterson got busted -- while already behind bars -- for hoarding prison wine in his cell, so now he's facing a new felony.
Law enforcement tells us ... Joshua Waring had the alcoholic beverage -- known as "pruno" in the can -- stashed in his bunk at an Orange County jail. We're told he's been charged with possession of contraband in a correctional facility.
Waring's in lockup awaiting trial for attempted murder, and is also facing a lawsuit from the man he allegedly shot.
Fun fact: Pruno is made with fruit, ketchup, sugar, milk and bread ... and is commonly mixed in toilet bowls. Before you whip some up for a holiday party -- it's been described as bile flavored.