Warner finished with 33-of-42 completions for 250 yards. Both scoring passes went to wide receiver Larry Fitzgerald.
Hightower scored on second- and fourth-quarter runs.
Steve Breaston caught seven passes for 77 yards.
Edgerrin James had 21 carries for 57 yards and a touchdown, and Neil Rackers booted two field goals for the Cardinals (3-2), who did not commit a turnover after seven in last Sunday's 56-35 setback against the New York Jets.
Buffalo backup quarterback J.P. Losman completed 15-of-21 passes for 220 yards, one touchdown and one interception.
Wide receiver Lee Evans caught two passes for 100 yards, one for an 87-yard, second-quarter touchdown, and Marshawn Lynch gained 55 yards on 13 carries for the 4-1 Bills, who lost starting quarterback Trent Edwards to a concussion on the third play from scrimmage.