The issue was resolved with additional restrictions on CSS compositing. This issue is fixed in tvOS 15, watchOS 8, iOS 15 and iPadOS 15. Visiting a maliciously crafted website may reveal a user's browsing history.
https://support.apple.com/en-us/HT212814
https://support.apple.com/en-us/HT212815
https://support.apple.com/en-us/HT212819
Source: MITRE
Published: 2021-08-24
Updated: 2021-12-22
Type: NVD-CWE-noinfo
Base Score: 4.3
Vector: AV:N/AC:M/Au:N/C:P/I:N/A:N
Impact Score: 2.9
Exploitability Score: 8.6
Severity: MEDIUM
Base Score: 4.7
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N
Impact Score: 1.4
Exploitability Score: 2.8
Severity: MEDIUM