The issue was addressed with improved checks. This issue is fixed in Safari 18.3, visionOS 2.3, iOS 18.3 and iPadOS 18.3, macOS Sequoia 15.3, watchOS 11.3, tvOS 18.3. Processing maliciously crafted web content may lead to memory corruption.
https://support.apple.com/en-us/122074
https://support.apple.com/en-us/122073
https://support.apple.com/en-us/122072
https://support.apple.com/en-us/122071