2:15 PM PT -- McGowan's attorney, Jose Baez, tells us, "Rose steadfastly maintains her innocence. These charges would have never been brought if it weren't for her activism as a voice for women everywhere. I assure you, this selective prosecution will be met with a strong defense."

Rose McGowan was just indicted by a grand jury in her ongoing cocaine possession case ... and could face jail time.

McGowan's been hit with one felony count of cocaine possession. As we reported, cops say back in January 2017 they found several small bags of cocaine in a wallet Rose had left behind on a flight at Washington Dulles International Airport.

McGowan pled not guilty to the charge ... saying she had been without the wallet for 5 hours before getting it back. Rose -- who was one of the first to stand up to Harvey Weinstein -- says she believed the disgraced movie mogul may have had a hand in planting the cocaine to damage her credibility.