The purpose of this study is to measure the efficacy and safety of KP-001 compared to placebo in patients with common venous malformations (VM), common lymphatic malformations (LM), or KTS/CLOVES syndrome. This phase 3, double-blind, randomized, placebo-controlled, parallel-group study will take place at multiple sites across North America. Vascular malformations like VM, LM, and KTS/CLOVES syndrome are serious, rare diseases with significant unmet medical needs. The study includes a 24-week double-blind treatment period with either KP-001 or placebo, followed by an open-label phase where all patients receive KP-001 up to Week 52. Patients weighing 40 kg or more will receive 100 mg of KP-001 once daily after breakfast, while those weighing less than 40 kg will receive a reduced dose based on their body weight.