Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1259

In JsRuntimeState::setCaller, it saves the current caller in the JsRuntimeState object(rcx+158h in 64-bit). But the garbage collector doesn't mark this saved value. So it results in a UAF.

Unlike in our test environment(Linux), it doesn't make reliable crashes on Windows. So I used another bug(#1258) to confirm the bug. If the UAF bug doesn't exist, the "crash" function will not be called(See poc.js).

The password of the zip file is "calleruaf"


Proof of Concept:
https://github.com/offensive-security/exploitdb-bin-sploits/raw/master/bin-sploits/42092.zip