CVE-2026-31712 Linux内核ksmbd越界读取漏洞

/* * PoC Concept for CVE-2026-31712 * This code demonstrates the structure logic that leads to the OOB read. * An attacker would create a file and set a custom DACL via SMB. */ #include <stdio.h> #include <stdint.h> // Malformed ACE structure definition struct malicious_ace { uint8_t type; uint8_t flags; uint16_t size; // Crafted size: 4 bytes (header only) // The following fields are missing in memory but accessed by the kernel: // uint32_t access_req; // struct smb_sid sid; }; int main() { printf("CVE-2026-31712 PoC Simulation\n"); printf("Vulnerability: ksmbd OOB read in smb_check_perm_dacl\n"); printf("Step 1: Authenticate to SMB server as low-priv user.\n"); printf("Step 2: Set a DACL on a file with an ACE where size=4.\n"); printf("Step 3: Trigger CREATE request on the file.\n"); printf("Result: Kernel reads access_req at offset+4 and SID at offset+8 (OOB).\n"); return 0; }