Security Expert from Google Zero Project released a PoC Exploit for Apple macOS
A bug discovered in macOS XNU kernel that allows
Copy-on-write ( referred to as “COW”) is an optimization strategy or resource management technique used in computer programming
So the copied memories should be protected from later modifications by the source process, if not then the source process might be able to exploit double-reads in the destination process.
According to Google Project Zero, “This copy-on-write behavior works not only with anonymous memory but also with file mappings. This means that, after the destination process has started reading from the transferred memory area, memory pressure can cause the pages holding the transferred memory to be evicted from the page cache. Later, when the evicted pages are needed again, they can be reloaded from the backing filesystem.”
In this case, Google published the Proof-of-concept that demonstrates this Zero-day flaw and also you can download the exploit here.
“This bug is subject to a 90-day disclosure deadline. After 90 days elapse or a patch has been made broadly available (whichever is earlier), the bug report will become visible to the public.”
Google always following Aggressive disclosure policies makes software vendors to strictly focus on their security bugs and keep them working and fix it as soon as possible.
Google Project zero