Villa looked to be heading out of the competition after Cristian Ciocoiu had struck twice in quick succession, the first off Michael Oakes after his shot had hit a post, before the interval.
At that stage Brian Little's side appeared to be in total disarray and, had Catalin Munteanu's effort gone in rather than hitting the crossbar early in the second half, the floodgates may well have opened. But Yorke left Villa needing only a 1-0 victory to take their place in the quarter- finals for the first time in 20 years.
It was sweet revenge for Yorke, who had been the subject of racist taunts along with Villa's other black players when they had inspected the stadium 24 hours earlier.
After his goal, Villa gradually regained their composure with Mark Draper outstanding as they re-established a grip on midfield.
Villa, who had recalled Ian Taylor in midfield and switched Fernando Nelson to full-back in place of Gary Charles, made a promising start.
Although Militaru flashed a free-kick just over the bar, Villa appeared to be taking the sting out of the Romanians and they should have taken the lead in the 17th minute through Mark Draper. The Villa midfielder sped past the challenges of Militaru and Tiberiu Csik to find himself unmarked on the edge of the area, but he screwed his shot hopelessly wide of the left-hand post.
The importance of this miss became apparent when Oakes was left cursing his luck as Ciocoiu grabbed the first of his two goals inside two minutes
Bucharest broke with lightning speed after the out-of-sorts Stan Collymore, sporting a new pair of pounds 2,500 boots, lost possession in the centre.
Munteanu fed the ball out to Lacatus and his pinpoint cross picked out Ciocoiu at the far post. His volley rattled against the post, but the rebound hit Oakes on the back of his hand and crossed the line.
Ciocoiu added the second Bucharest goal in the 32nd minute. A cross from the right by Rotariu picked out Ciocoiu and he beat Oakes with a spectacular overhead kick from around 12 yards.
Steaua continued in the same vein after half-time, but the pendulum swung back Villa's way in the space of 60 seconds when they could have gone 3-0 behind but instead halved the deficit.
Munteanu's effort from close range rattled against the underside of the bar and then Yorke, who had scored the decisive goal in the win over Athletic Bilbao, did it again.
Collymore and Wright engineered space for Savo Milosevic on the left flank and he sent in a centre which Yorke sent into the corner of the net with a glancing header. The home side were rattled and Yorke sent another header just wide from a Wright centre.
Villa came within inches of an equaliser 15 minutes from time. A free- kick from Wright picked out Milosevic and his volley flew inches past the post.
"We said at half-time that we've got to hang in there and if we get one back, we've got to get the same result we've been getting in all the other rounds," Little said. "Thankfully, we got it and we've given ourselves a chance.
"They're a good side, they made it hard for us and they have some lively players. Their results this season have seen them go through on away goals.
"We're learning a lot, but we go home with everybody thinking we've got a chance and that's the main thing."
Steaua Bucharest: Ritli; Reghecampf, Miu, Artariu, Rachita, Lacatus (Raducan, 88), Militaru, Ciocoiu (Luca, 76), Munteanu, Lincar (Hrib, 70), Csik.
Aston Villa: Oakes; Nelson (Charles, 70), Staunton, Ehiogu, Taylor, Draper, Milosevic, Yorke, Collymore, Wright, Scimeca.
Referee: Luvos Michel (Hungary).Reuse content