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CVE-2026-2636 is a local denial-of-service vulnerability in the Windows Common Log File System (CLFS) kernel driver (CLFS.sys). The issue is attributed to improper handling/validation of special elements/flags (CWE-159) in CLFS!CClfsRequest::ReadLogPagingIo, where the driver can process an I/O Request Packet (IRP) with critical flags disabled (notably IRP_PAGING_IO and IRP_INPUT_OPERATION). When both flags are absent (e.g., AL=0x0 in the reported path), the function follows an incorrect execution path that results in a deterministic call to nt!KeBugCheckEx, crashing the system (BSoD). Public PoC exploitation is described as requiring only CreateLogFile to obtain a .blf handle followed by ReadFile on that handle, without crafted files or memory-corruption primitives. The behavior was observed on CLFS.sys 10.0.22621.5037.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos (1 hidden).
Repository is a small Visual Studio C++ console project providing a PoC for CVE-2026-2636 (Windows CLFS.sys). Structure: a VS solution (ConsoleApplication12.sln) and project files (ConsoleApplication12.vcxproj/.filters) plus a single source file (ConsoleApplication12/CVE-2026-2636_PoC.cpp), README, and AGPL license. Core behavior (CVE-2026-2636_PoC.cpp): - Deletes a local file named "MyLogFile.blf" (DeleteFile). - Calls CreateLogFile with CLFS path "LOG:MyLogFile" and GENERIC_READ|GENERIC_WRITE, FILE_SHARE_READ|FILE_SHARE_WRITE, OPEN_ALWAYS, FILE_FLAG_OVERLAPPED. - Immediately calls ReadFile on the returned CLFS handle using an OVERLAPPED structure. - On failure it prints GetLastError and exits; on success it prints buffer contents; then shows a MessageBox. Exploit capability: local, unprivileged denial-of-service by triggering a CLFS.sys unrecoverable state/bugcheck via an unusual but simple API call sequence (CreateLogFile -> ReadFile). No networking, no shellcode, and no crafted log content is included; it is a minimal crash trigger PoC rather than an RCE exploit.
7 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
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