The fixes in 14.5.1 are not in 14.4.2, but you also cannot easily determine whether or not 14.4.2 is affected by those particular exploits. Given that 14.5 already fixed things in WebKit that were under active exploit in 14.4.2, it's imprudent to stay with anything older than 14.5.1.If we can get any identification for the exploits (the number, the name) we can compare between the exploits 14.4.2 patched and the ones 14.5.1 patches. We compare and if they are the same IDs, it’s the same patch. If they differ, that means the exploits are present in 14.4.2