United were strongly linked with a move for the 19-year-old before he left Galatasaray in January.
According to the Daily Mail, Stuttgart's relegation from the Bundesliga means that the centre-back is available for just over £13m in this summer's transfer window.
The report has claimed that United have 'rekindled' their interest, although the Red Devils will face competition from Arsenal and Tottenham Hotspur if they move for the teenager ahead of the 2019-20 campaign.
Kabak made 18 appearances for Galatasaray before a January move to Stuttgart, where he finished the season with three goals in 17 games.
The defender has represented Turkey at Under-15, Under-16, Under-17 and Under-18 level. body check tags ::