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CVE-2026-33827 is a Critical remote code execution vulnerability in the Windows TCP/IP stack, associated with concurrent execution using a shared resource with improper synchronization. Available reporting further characterizes the flaw as a race condition in tcpip.sys that can lead to a use-after-free condition during processing of specially crafted IPv6 traffic on systems with IPSec enabled. Successful exploitation does not require authentication or user interaction and is achieved by sending crafted network packets to a reachable vulnerable Windows host.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
Repository is very small and consists of a long README plus a single Python PoC script. The README describes an alleged Windows TCP/IP IPv6/IPSec race-condition RCE, CVE-2026-33827, affecting Windows 10/11/Server and requiring network reachability plus IPSec. It includes defensive guidance, references, and high-level exploitation theory, but no concrete exploit internals beyond pseudocode. The actual code in exploit.py is a Scapy-based packet generator. It defines a placeholder target IPv6 address (fe80::...) and interface (eth0), builds an Ethernet frame carrying an IPv6 packet with a Destination Options header, an IPv6 Fragment header with randomized fragment ID, and a 1200-byte raw payload of repeated 'X' characters. The flood() function then repeatedly transmits this packet at Layer 2 using sendp(..., loop=1, inter=0), effectively creating a continuous malformed/fragmented IPv6 packet flood. Main exploit capability: network-based packet crafting and flooding intended to stress or trigger the claimed vulnerable Windows IPv6/IPSec processing path. The script does not implement IPSec negotiation, race orchestration across threads/processes, memory corruption primitives, shellcode delivery, callback infrastructure, or any reliable RCE chain. As such, this is best characterized as a proof-of-concept traffic generator rather than a complete weaponized exploit. Repository structure and purpose: README serves as vulnerability overview and remediation guidance; exploit.py is the only executable component and the likely entry point. Overall purpose appears to be demonstrating how to generate suspicious IPv6 fragmented traffic against a Windows target, not delivering a full end-to-end compromise.
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18 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A remote unauthenticated race condition and use-after-free vulnerability in the Windows IPv4 stack (tcpip.sys) triggered by crafted packets with the Strict Source and Record Route option.
A critical remote unauthenticated remote code execution vulnerability in Windows tcpip.sys triggered via IPv4 Strict Source and Record Route processing.
A remote code execution vulnerability in Windows TCP/IP that could allow remote unauthenticated code execution and may be wormable on systems with IPv6 and IPSec enabled.
A critical remote code execution vulnerability in the Windows TCP/IP stack triggered by a specially crafted IPv6 packet against systems with IPSec enabled.
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Cross-references every affected SKU, including bundled OEM variants.
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