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CVE-2026-21250 is an elevation of privilege vulnerability in Windows HTTP.sys caused by an untrusted pointer dereference. The flaw allows a local authorized attacker to trigger unsafe pointer handling within the HTTP.sys kernel-mode HTTP protocol stack and elevate privileges on the affected Windows system. Available information identifies the bug class and affected component, but does not provide the specific vulnerable function or code path.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos (1 hidden).
Repository contains two C source files and two Markdown documents. The main executable PoC is Exploit.c, a Windows Winsock-based client that connects to 127.0.0.1:80 and sends a handcrafted HTTP request with a custom header, X-Trigger-Ptr, followed by 8 raw bytes (default all 0x00). The code carefully uses memcpy and send(..., offset, ...) so embedded null bytes are transmitted intact, indicating the core research goal is to test whether HTTP.sys mishandles binary header data and dereferences attacker-controlled pointer content. Exploit_advanced.c is not a complete standalone exploit; it is a helper-style payload builder that constructs a more realistic HTTP request to /index.php with randomized parameters and the same pointer-bearing header. README.md frames the repository as research for CVE-2026-21250, described as an HTTP.sys untrusted pointer dereference leading to local privilege escalation on recent Windows 11 and Windows Server builds. Use.md contains conceptual offensive notes on heap spraying, header obfuscation, keep-alive/race-condition ideas, and post-exploitation tradecraft, but these are documentation only and not implemented in the code. Overall, this is a low-maturity proof-of-concept/research repository: it demonstrates malformed network input delivery to HTTP.sys, but it does not include a working privilege-escalation chain, shellcode delivery, or reliable SYSTEM-level payload.
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8 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A privilege escalation vulnerability affecting Windows HTTP.sys.
An elevation of privilege vulnerability in Windows HTTP.sys.
An elevation of privilege vulnerability in Windows HTTP.sys (no additional details provided in the content).
An elevation of privilege vulnerability in Windows HTTP.sys.
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