A privacy issue was addressed with improved handling of identifiers. This issue is fixed in iOS 27 and iPadOS 27, macOS Golden Gate 27, visionOS 27. An app may be able to identify a user across reinstalls.

{
                    "vendor": "Apple",
                    "product": "iOS and iPadOS",
                    "versions": [
                        {
                            "version": "0",
                            "status": "affected",
                            "lessThan": "27",
                            "versionType": "custom"
                        }
                    ]
                }

{
                    "vendor": "Apple",
                    "product": "macOS",
                    "versions": [
                        {
                            "version": "0",
                            "status": "affected",
                            "lessThan": "27",
                            "versionType": "custom"
                        }
                    ]
                }

{
                    "vendor": "Apple",
                    "product": "visionOS",
                    "versions": [
                        {
                            "version": "0",
                            "status": "affected",
                            "lessThan": "27",
                            "versionType": "custom"
                        }
                    ]
                }