The issue was addressed with improved UI handling. This issue is fixed in Safari 26.5, iOS 26.5 and iPadOS 26.5, macOS Tahoe 26.5, visionOS 26.5. A malicious iframe may use another website’s download settings.
https://isc.sans.edu/diary/rss/32976
https://support.apple.com/en-us/127121
https://support.apple.com/en-us/127120