Gash was allowed to leave the Abbey Stadium and rejoin part-time neighbours Cambridge City two years ago after only being used fleetingly by the U’s.
The Minstermen’s £55,000 striker, though, earned the home side a point with a terrific 89th-minute header after earlier firing Martin Foyle’s men into a first-half lead.
Two goals in four minutes from Jai Reason and substitute Mark Beesley looked to have turned the match on its head, but City extended their unbeaten home run to an eighth game thanks to Gash.
City boss Martin Foyle made a first change to his starting line-up in five fixtures with Alex Lawless ruled out through illness.
As a result, Levi Mackin was pitched in for his first start since mid-August as the home side’s midfield anchor man.
The first half saw Cambridge become the only visiting side to match the Minstermen’s high tempo at Bootham Crescent this season.
City, though, still managed the opening shot of the night when Mackin’s ten-yard effort was deflected wide off Andy Parkinson.
Gash also miscued an early edge-of-the-box chance that troubled the corner flag rather than visiting keeper Danny Potter’s goal.
On 15 minutes, former City trialist Reason drove wide from 20 yards after Daniel Parslow had headed away a Robbie Willmott corner.
Danny Crow, cutting in from the left, then forced Michael Ingham into a near-post save with a bouncing effort.
Shortly afterwards, City’s talented strikeforce of Gash and Richard Brodie, who had been successfully contained by uncompromising Cambridge defenders Brian Saah and Wayne Hatswell, combined unwittingly to break the deadlock.
A goalbound Ferrell shot struck Brodie and fell fortuitously to Gash who showed great reactions to pounce on the loose ball and sidefoot past Potter from eight yards.
City then finished the half strongly with Gash attempting an acrobatic overhead kick that forced Potter into his second save of the night.
The Cambridge keeper also scrambled a Brodie free-kick around his near post seconds before the interval.
Martin Ling’s men responded strongly at the start of the second half with Crow ghosting in between Parslow and Ingham to collect a long Dan Gleeson pass only to make a hash of his finish.
The Minstermen might have doubled their lead moments later, however, when Gash released Brodie for a free run on goal. But City’s leading marksman lost his footing and was falling over as he shot wide of Potter’s near post.
Djoumin Sangare also sent a glancing header wide from Barrett’s corner before Cambridge substitute Lee Phillips almost equalised with his first touch.
The former Torquay striker rose high to meet Anthony Tonkin’s 77th-minute cross but headed narrowly over.
Two minutes later, Cambridge were level when Reason fired deliberately into Ingham’s bottom right-hand corner from the edge of the box after a slick passing move.
On 83 minutes, the visitors forged ahead when centre-back Saah drove forward passed the ball into the penalty box and Beesley was left clear through on goal after a clever decoy run by Willmott.
Beesley’s calm sidefooted finish into Ingham’s bottom left-hand corner from ten yards left the City keeper helpless.
The last word was left to Gash, though, on 89 minutes when his towering header eight yards out from Smith’s pinpoint right-wing cross sailed over the head of Potter.
York City 2 (Gash 35, 89), Cambridge United 2 (Reason 79; Beesley 83)
York City: Michael Ingham 7, Ben Purkiss 8, Djoumin Sangare 8, Daniel Parslow 7, James Meredith 7, Adam Smith 7, Neil Barrett 7, Levi Mackin 7, Andy Ferrell 8, Michael Gash 8, Richard Brodie 7.
Not used: Pacquette, Nelthorpe.
Key: 10 – Faultless; 9 – Outstanding; 8 – Excellent; 7 – Good; 6 – Average; 5 – Below par; 4 – Poor; 3 – Dud; 2 – Hopeless; 1 – Retire.
City’s star man: Michael Gash – two well-taken goals to earn City a point.
Cambridge: Danny Potter, Dan Gleeson, Brian Saah, Wayne Hatswell, Anthony Tomkin, Andy Parkinson (Courtney Pitt 69), Jai Reason, Paul Carden, Robbie Willmott, Chris Holroyd (Lee Phillips 74), Danny Crow (Mark Beesley 74).
Subs: Josh Coulson, Sam Ives.
Yellow cards: Brodie 85, Willmott 85.
Shots on target: York 5, Cambridge 2.
Shots off target: York 5, Cambridge 4.
Corners: York 4, Cambridge 6.
Fouls: York 14, Cambridge 9.
Offsides: York 2, Cambridge 2.
Referee: Jeremy Simpson (Lancashire).
Attendance: 2,321 (234 away).