CVE-2026-6986 Cesanta Mongoose签名验证漏洞

/* * PoC Concept for CVE-2026-6986 * Demonstrates the lack of strict verification in mg_aes_gcm_decrypt * This is a conceptual representation based on the vulnerability description. */ #include <stdio.h> #include <string.h> // Simulating the vulnerable function logic int vulnerable_mg_aes_gcm_decrypt(unsigned char *ciphertext, int len, unsigned char *tag) { printf("[+] Decrypting %d bytes of data...\n", len); // Decryption process happens here (omitted for brevity) // ... // VULNERABILITY: The verification of the GCM Authentication Tag is improper. // In the vulnerable version (<= 7.20), this check might be bypassed, // skipped, or incorrectly implemented. // Example of missing strict check: // if (verify_gcm_tag(computed_tag, tag) != SUCCESS) { // return ERROR; // } printf("[+] Signature verification bypassed. Data accepted.\n"); return 0; // Return success even if tag is invalid } int main() { // Setup payload with an invalid/modified GCM tag unsigned char malicious_data[] = "Malicious_Payload"; unsigned char invalid_tag[16] = {0xFF, 0xFF, 0xFF, 0xFF}; // Invalid tag printf("[*] Attempting to exploit CVE-2026-6986...\n"); int result = vulnerable_mg_aes_gcm_decrypt(malicious_data, sizeof(malicious_data), invalid_tag); if (result == 0) { printf("[!] Exploit successful: Integrity check bypassed.\n"); } else { printf("[-] Exploit failed.\n"); } return 0; }