Swansea's teenage substitute Joe Allen looked to have secured victory in a clash of high drama at Ninian Park with a fine 88th-minute strike.
But McCormack stepped up after referee Mike Dean deemed the Scottish striker had been pushed by Ashley Williams inside the box.
Michael Chopra had restored parity with his ninth goal of the season after Nathan Dyer's opener.
Both managers appealed for calm ahead of the first league South Wales derby at Ninian Park since 1999 and the final one before Cardiff move to their new stadium this summer.
Bluebirds boss Dave Jones recalled Stephen McPhail to his starting line-up in place of Gavin Rae while Jason Scotland was passed fit.
The eagerly-awaited clash began in lively fashion when referee Dean turned down a third-minute penalty appeal by the visitors.
Swansea midfielder Jordi Gomez fell to the ground under the challenge of Paul Parry but his appeal was waved away by the Premier League official.
The hosts responded a minute later with the first chance of the game when McCormack blazed over inside the penalty box.
Cardiff enjoyed the early possession but Swansea took the lead in the 11the minute when the pacy Dyer combined with Scotland before firing his slot past Stuart Taylor for his third goal of the season.
The visitors nearly doubled their advantage six minutes later when Gomez saw his dipping effort drop inches over the crossbar.
The hosts rallied and Parry should have levelled the contest but the winger's finish from eight yards lacked conviction after Dorus De Vries had parried McCormack's fizzing free-kick.
Cardiff were piling on the pressure and, in the 24th minute, Chopra was only denied by De Vries' left-hand post.
The former Sunderland striker then turned provider on the half-hour mark when his header set up Joe Ledley who failed to make a clean contact.
The game turned nasty two minutes before the interval when Wirral-based Dean was hit by a coin above the right eye from the home supporters.
Roberto Martinez's men started the second half brightly and, after Gomez's 25-yard shot had been palmed away by Taylor, Dyer followed up and looked to have scored.
But Darren Purse came to Cardiff's rescue with a crucial goal-line clearance.
That timely intervention spurred the home side on and Cardiff's equaliser came in the 54th minute.
Parry's deep cross to the back post broke the Swansea offside trap to find the lurking Jay Bothroyd who squared to Chopra for the simplest of tap-ins.
The Bluebirds were on the front foot and McCormack kept the noise levels high with a rasping drive which flew over.
Cardiff maintained their superiority into the final quarter of the match when
Bothroyd saw his free-kick deflected wide before a burst by Ledley forced De Vries into a smart save down low to his right-hand side.
But then came a rousing finish when 19-year-old Allen fired past Taylor from 25 yards before McCormack showed ice-cool composure to hand the hosts a deserved point.