Microsoft IE: Memory curruption in CMarkup::DestroySplayTree CVE-2017-8594 There is a memory corruption issue in IE that can be triggered with svg element. The bug was confirmed on IE Version 11.0.9600.18617 (Update Version 11.0.40) running on Windows 7 64-bit. I was unable to reproduce it on Windows 10. PoC: ========================================== http://www.w3.org/1999/xhtml">2)lt ========================================== Following is the crash log when the PoC is ran on 64-bit IE in the single process mode (TabProcGrowth=0). (1a38.2a98): Access violation - code c0000005 (first chance) First chance exceptions are reported before any exception handling. This exception may be expected and handled. MSHTML!CMarkup::DestroySplayTree+0x10a: 000007fe`e8de2723 48894110 mov qword ptr [rcx+10h],rax ds:00000000`700400d6=???????????????? 0:013> r rax=0000000012a69010 rbx=0000000012a68c78 rcx=00000000700400c6 rdx=0000000000000001 rsi=0000000012a68f20 rdi=0000000012a58000 rip=000007fee8de2723 rsp=0000000012d9bfb0 rbp=0000000012d9c029 r8=0000000000000000 r9=0000000012a58000 r10=0000000012a20000 r11=0000000000000025 r12=0000000012a68f20 r13=0000000012a68f20 r14=0000000012a20000 r15=0000000012a68bb0 iopl=0 nv up ei pl zr na po nc cs=0033 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010246 MSHTML!CMarkup::DestroySplayTree+0x10a: 000007fe`e8de2723 48894110 mov qword ptr [rcx+10h],rax ds:00000000`700400d6=???????????????? 0:013> k # Child-SP RetAddr Call Site 00 00000000`12d9bfb0 000007fe`e8de1ddc MSHTML!CMarkup::DestroySplayTree+0x10a 01 00000000`12d9c090 000007fe`e8ec9289 MSHTML!CMarkup::UnloadContents+0x49b 02 00000000`12d9c170 000007fe`e8ec9171 MSHTML!CMarkup::TearDownMarkupHelper+0xd5 03 00000000`12d9c1a0 000007fe`e90788b2 MSHTML!CMarkup::TearDownMarkup+0x75 04 00000000`12d9c1f0 000007fe`e998dc7a MSHTML!COmWindowProxy::SwitchMarkup+0x562 05 00000000`12d9c360 000007fe`e969ce9f MSHTML!COmWindowProxy::ExecRefresh+0xa3a 06 00000000`12d9c500 000007fe`e8d99d75 MSHTML!GlobalWndOnMethodCall+0x240 07 00000000`12d9c5a0 00000000`76dd9bbd MSHTML!GlobalWndProc+0x150 08 00000000`12d9c620 00000000`76dd98c2 USER32!UserCallWinProcCheckWow+0x1ad 09 00000000`12d9c6e0 000007fe`f2f83395 USER32!DispatchMessageWorker+0x3b5 0a 00000000`12d9c760 000007fe`f2f7df5b IEFRAME!CTabWindow::_TabWindowThreadProc+0x555 0b 00000000`12d9f9e0 000007fe`fd09572f IEFRAME!LCIETab_ThreadProc+0x3a3 0c 00000000`12d9fb10 000007fe`f0b7925f iertutil!Microsoft::WRL::ActivationFactory,Windows::Foundation::IUriEscapeStatics,Microsoft::WRL::Details::Nil,0>::GetTrustLevel+0x5f 0d 00000000`12d9fb40 00000000`76ed59cd IEShims!NS_CreateThread::DesktopIE_ThreadProc+0x9f 0e 00000000`12d9fb90 00000000`7700a561 kernel32!BaseThreadInitThunk+0xd 0f 00000000`12d9fbc0 00000000`00000000 ntdll!RtlUserThreadStart+0x1d This bug is subject to a 90 day disclosure deadline. After 90 days elapse or a patch has been made broadly available, the bug report will become visible to the public. Found by: ifratric