CVE-2026-31681 Linux内核netfilter越界读取漏洞

/* * PoC Concept for CVE-2026-31681 * Trigger: Kernel panic via malformed iptables multiport rule */ #include <stdio.h> #include <string.h> // Conceptual structure of the vulnerable rule data struct xt_multiport_v1 { __u8 flags; // Flags indicating range start __u8 count; // Number of ports __u16 ports[]; // Port array }; int main() { printf("[*] CVE-2026-31681 PoC Concept\n"); printf("[*] Vulnerability: xt_multiport lacks range validation in checkentry\n"); printf("[*] Impact: Out-of-bounds read in ports_match_v1 leading to DoS\n\n"); // To trigger this, one would typically use netlink to add a rule // where the last port has a range flag set (IP6T_MULTIPORT_RANGE), // forcing the kernel to read past the allocated ports array. printf("[!] Exploitation requires sending a malformed netlink message\n"); printf("[!] or modifying iptables tool to bypass user-space checks.\n"); printf("[!] Example payload logic: Set range flag on last port index.\n"); return 0; }