A permissions issue was addressed with additional restrictions. This issue is fixed in iOS 18.4 and iPadOS 18.4, iPadOS 17.7.9. An app may be able to read a persistent device identifier.
https://support.apple.com/en-us/124148
https://support.apple.com/en-us/122371
https://euvd.enisa.europa.eu/vulnerability/EUVD-2025-14861