In his first Premier League start for nearly two years, Murphy caught out goalkeeper Rui Patricio with a strike into the bottom corner.
Wolves, who would have moved up to fourth with victory, led through Raul Jimenez's 80th-minute volley from 25 yards out, after a free-kick had been headed clear.
Earlier Pedro Neto had driven just over the bar for Wolves while Jimenez was denied by Karl Darlow before his goal.
Allan Saint-Maximin had the Magpies' best chance aside from the goal, but his effort was saved by Patricio.
Wolves are seventh in the table while Newcastle are 14th.
Budweiser King of the Match: Raul Jimenez
Wolves: 30 Oct v Crystal Palace (H)
Newcastle: 1 Nov v Everton (H)