Vokes tapped home from Ashley Barnes' pass in the 89th minute to salvage a share of the spoils for the Seagulls after Peter Whittingham's fine strike looked to have won the game for the visiting Bluebirds.
Earlier, Barnes had levelled matters for Gus Poyet's hosts following Joe Mason's opener for the visitors, but a point does neither side much good in their bid for a place in the npower Championship play-offs.
Cardiff manager Malky Mackay handed a debut to on-loan midfielder Liam Lawrence in place of the injured Rudy Gestede, who missed out because of a hamstring injury, while Brighton were unchanged from the side that drew 1-1 at Doncaster.
After a scratchy first 15 minutes, Brighton came close to taking the lead when Craig Mackail-Smith's drilled effort was turned round the post well by David Marshall.
It took until 24 minutes for the visiting Bluebirds to put together a decent passage of possession, at the end of which Peter Brezovan did well to hold onto Kenny Miller's snapshot.
Mackail-Smith blasted a free-kick well over the crossbar and Gonzalo Jara Reyes hit a post following a Liam Bridcutt free-kick, as Cardiff chose to sit back and absorb long spells of pressure from their hosts.
After making it through until half-time with the score goalless, Cardiff found their feet and went ahead after 56 minutes.
Mark Hudson found Mason in the area and the former Plymouth striker produced a clinical finish past Brezovan to give the Bluebirds the lead.
Poyet responded to going behind by making a triple substitution, with Craig Noone, Will Buckley and Vokes entering the game, and the Seagulls were almost level soon after.
First, Vokes' effort from 18 yards was claimed by Marshall before Barnes was denied twice in a matter of seconds, first by a crucial block from Hudson and then by another fine Marshall save.
However, Cardiff could not hold out for long and Brighton levelled when Noone picked out Barnes 12 yards from goal and the dangerous forward slotted beyond Marshall.
The Welsh outfit were not on level terms for long, though.
Just two minutes after the restart the ball broke to Whittingham on the edge of the box and he picked his spot in the top left-hand corner of the net.
It appeared Cardiff would claim the win necessary to lift them back into the top six, but with a minute remaining Vokes found space to slide home Barnes' neat centre to snatch a point.