The former couple's private St Bart's vacation pics leaked online after the One Direction singer's mother Anne Cox's iCloud account was hacked by a fan, reported Us magazine.
More than two dozen photos were obtained and posted on the Internet, causing the unauthorized leak to trend on Twitter as "Anne's iCloud", reported Us magazine.
In the intimate shots, Styles, 22, and Jenner, 20, are pictured cozying up on a yacht in their swimsuits over New Year's weekend.
Several of the pictures also show the "Keeping Up With the Kardashians" star, who rocked a barely there black bikini, sitting on the entertainer's lap.
Shortly after the hack, Cox, 48, deleted her Twitter and Instagram accounts as fans continued to share the personal snaps from her account.