Should Leinster beat Wasps they will qualify for the quarter-finals but a home tie is only guaranteed should they add a bonus point.
An unexpected defeat could spell trouble should results from the other pools not go their way with the possibility that eight others teams finish on more than 20 points.
Toulouse are likely to qualify with a win over Bath at home.
A win or a draw against Exeter will be enough for Munster to top the pool. However, the current Premiership leaders, after an impressive win over Castres, have their own agenda.
A win for Rob Baxter's team, while denying Munster a bonus point would be enough to make the knock-out stages as they would have a better head-to-head record, having drawn the opening game against Johann van Graan's men at Sandy Park.
However, victory for the English side with a four-try bonus point would mean that Munster would need to earn two losing points, i.e. lose by seven or less and score four tries.
As for a home draw, Munster want Montpellier to beat Edinburgh away and deny the hosts bonus points.
Racing 92 are at home to out-of-contention Scarlets so Ulster won't be holding out for an upset in order to qualify as table-toppers.
The 1999 champions must focus on their own task, which is beating bottom of the pool Leicester at Welford Road.
After that it gets more interesting and they will be waiting on results from the other pools to go their way.
In contrast to Munster, Dan McFarland will be hoping that Edinburgh get their fifth win of the pool against Montpellier in order to edge ahead in the second-place race.
Other than that, Ulster fans will be keeping an eye on Pool 3 where they want Saracens to beat Glasgow at home, and have their fingers crossed for Munster against Exeter in Pool 2.
With Sale at home to the hapless Perpignan, it's realistically a battle for one of three best runners-up spots.
Connacht, on 17 points, lead the mini-table of second-place teams across the five Challenge Cup pools and a win away against out-of-contention Bordeaux-Begles on Saturday would be enough to qualify.