The 36-year-old reality star said he was "desperate" to get back at her eldest sister by cavorting with the 20-year-old actress Bella Thorne in Cannes.
Addressing the topic of the father of Kourtney's three children Scott, the most famous member of the Kardashian clan Kim said she thought his rumored fling with the Bella was all for attention.
Former boyfriend and girlfriend: Scott Disick and Kourtney Kardashian with their three children
Talking to her younger sister Kendall Jenner about the 34-year-old Scott's very hands-on holiday with Bella, Kim said;
They looked so desperate at the airport. Who goes to LAX together? It's not a good look for Scott.
In response, the 21-year-old model Kendall revealed;
He talked to me about it. He thinks it is and I said, 'Are you nuts? Are you actually not well? And he was like, 'Yeah, I'm doing it to make Kourtney mad.' I said, 'You're not going to make her mad for the right reasons.
Taking things a step further, Kim added;
I think it's clear to everyone that Scott's doing this just to try to one-up Kourtney and that seems super malicious. Kourtney's genuinely trying to go away and have a good time and he's trying to like freak her out and make Kourtney think there's going to be some crazy drama run-in. It's just so ridiculous.
Video: Kim Kardashian brands Scott ‘malicious’ for dating Bella Thorne to get revenge on ex Kourtney
This comes as both Kourtney and Scott, who had been dating for nine years, have moved on following a prolonged split.