CVE-2026-67398Missing authorization vulnerability has been discovered in 2Checkout payment gateway of WHMCS from 8.13.0 before 8.13.8, from 9.0.0 before 9.0.8, all other EOL versions from 4.5.0. The vulnerability allows an unauthenticated user to get WHMCS customer's data via 2Checkout payment gateway's endpoint under specific conditions.