A cookie management issue was addressed with improved state management. This issue is fixed in watchOS 11, macOS Sequoia 15, Safari 18, visionOS 2, iOS 18 and iPadOS 18, tvOS 18. A malicious website may exfiltrate data cross-origin.
https://support.apple.com/en-us/121250
https://support.apple.com/en-us/121249
https://support.apple.com/en-us/121248
https://support.apple.com/en-us/121241