Credit is to "Nils Sommer of bytegeist, working with Google Project Zero".

I reproduced the blue screen immediately in my Win 7 32-bit VM.

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The attached PoC demonstrate a use-after-free condition that occurs when operating on a DeferWindowPos object from multiple threads. The DeferWindowPos() call will trigger and block on the execution of a window procedure in a separate thread from which we call EndDeferWindowPos on the same handle. specialpool.txt contains the debugger output with Session Pool enabled, crash.txt the debugger output without Session Pool.
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This bug is subject to a 90 day disclosure deadline. If 90 days elapse
without a broadly available patch, then the bug report will automatically
become visible to the public.

 

crash339.txt 1.9 KB View Download

bug339.cpp 4.2 KB Download

specialpool339.txt 9.4 KB View Download