England under-21 international winger Kightly, who damaged his ankle against West Bromwich Albion five months ago, set the seal on the victory with a 56th minute tap-in.
Andy Keogh had put Wolves in control when he struck after just eight minutes to take his tally for the season to 11 with Sylvan Ebanks-Blake's 24th goal of the campaign on the stroke of half-time doubling their advantage.
Wolves now stand just two points behind sixth placed Crystal Palace and in with a chance of reaching the play-offs for a second successive season.
Cardiff, without an away league win since beating Preston on December 29, wilted after Ebanks-Blake's strike and will need to carry more of a threat for their big date at Wembley against Portsmouth.
Keogh gave Wolves the perfect start when he met a Kevin Foley cross with a powerful header from eight yards.
That was the only time Wolves really threatened before Ebanks-Blake added a second on the stroke of half-time and Cardiff were left wondering how they went into the break trailing 2-0.
With the impressive Cardiff winger Peter Whittingham causing mayhem on the left flank and Gavin Rae running the midfield, City outplayed Wolves for long spells.
But they could not their turn their impressive build-up play into goals with Whittingham and Joe Ledley having shots blocked and Jimmy Floyd-Hasselbaink seeing his point-blank drive saved by Wayne Hennessey.
Welsh international Hennessey also denied Ledley before Wolves made Cardiff pay for failing to take their chances.
Foley was once again the creator, lifting over another right-wing cross that Keogh headed down for Ebanks-Blake to stab the ball home on the line.
That was the goal which signalled the end for Cardiff's challenge and Wolves made the game safe 11 minutes into the second half.
Ebanks-Blake turned on the edge of the area and fired in a low drive that Peter Enckelman was unable to hold.
Kightly reacted faster than the Cardiff defence and stabbed the ball into an empty net.
Cardiff's dismal day was summed up after 62 minutes when they were denied a consolation strike with Hennessey pulling off a stunning one-handed save to frustrate Hasselbaink for a second time.