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

I managed to get a bluescreen out of this on first try with Win 7 32-bit, special pool enabled on win32k.

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The PoC bug checks reliably with Special Pool enabled on writing to freed memory. A reference to the freed memory is held at offset +0x10 of the THREADINFO object. This memory is referenced in HmgAllocateObjectAttr which is called in multiple locations. The freed memory is a struct inside a Brush Object which is freed in the call NtGdiDeleteObjectApp.
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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.

 

bug320.cpp 2.8 KB Download

special_pool_crash.txt 6.7 KB View Download