So often the Canaries' star player this season, Buendia was shown a second yellow card for a needless lunge on George Saville, leaving the leaders to play the final quarter of the game with 10 men.
The dismissal brought Boro out of their shells after a strong defensive display but they could find no way beyond an equally-determined Norwich rearguard as the points were shared.
The draw strengthened Norwich's position at the top, while for the visitors it was a welcome boost after successive home defeats.
Norwich were in complete control in the early stages and wasted a wonderful chance to open the scoring in the seventh minute.
Mario Vrancic did well to spot a gap in the well-drilled Boro defence and burst through it but he was forced to shoot with his weaker right foot and screwed the effort just wide from a good position.
The midfielder also fired high and wide from just outside the box while Lukas Rupp headed Buendia's free-kick over as the Canaries struggled to find a way through.
As the half progressed Boro spent more time in the opposition half and new loan signing Yannick Bolasie had their first effort on goal in the 26th minute when he directed a header from an inswinging free-kick just over.
Neil Warnock's plan to frustrate the leaders had worked a treat in the opening period and, although Todd Cantwell sent an effort narrowly wide just after the break, the Canaries continued to find it tough going against well organised opposition.
The game's first effort on target finally arrived on the hour mark when Jonny Howson's header from a corner brought as routine save out of Tim Krul - and six minutes later things took a distinct turn for the worse for the leaders.
Star man Buendia, who had already been booked for a first-half foul, unwisely slid in to challenge Saville near the centre circle and caught the Boro man late.
Referee Keith Stroud allowed play to continue but when the move broke down he called the Argentinian over and brandished a second yellow.
With an extra man Boro pushed more men forward in search of an equaliser but Marc Bola's low skidder into Krul's arms was the best they could muster as Norwich comfortably held on for a share of the spoils.
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