This issue was addressed with additional entitlement checks. This issue is fixed in iOS 18.5 and iPadOS 18.5, iPadOS 17.7.7, macOS Sequoia 15.4, macOS Sonoma 14.7.6, macOS Ventura 13.7.6, visionOS 2.5. An attacker may be able to turn on sharing of an iCloud folder without authentication.
https://support.apple.com/en-us/122721
https://support.apple.com/en-us/122718
https://support.apple.com/en-us/122717
https://support.apple.com/en-us/122405
https://support.apple.com/en-us/122404
https://support.apple.com/en-us/122373
http://seclists.org/fulldisclosure/2025/May/9