USN-8087-1 fixed a vulnerability in python-cryptography. The update caused
a regression when using ECC algorithms with certain software. This update
fixes the problem.
We apologize for the inconvenience.
Original advisory details:
It was discovered that python-cryptography incorrectly handled subgroup
validation for SECT curves. A remote attacker could use this issue to
perform a subgroup attack and possibly recover the least significant bits
of private keys.
cryptography Subgroup Attack Due to Missing Subgroup Validation for SECT Curves
cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. Prior to 46.0.5, the public_key_from_numbers (or EllipticCurvePublicNumbers.public_key()), EllipticCurvePublicNumbers.public_key(), load_der_public_key() and load_pem_public_key() functions do not verify that the point belongs to the expected prime-order subgroup of the curve. This missing validation allows an attacker to provide a public key point P from a small-order subgroup. This can lead to security issues in various situations, such as the most commonly used signature verification (ECDSA) and shared key negotiation (ECDH). When the vi
cryptography NULL pointer deference with pkcs12.serialize_key_and_certificates when called with a non-matching certificate and private key and an hmac_hash override
cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. Starting in version 38.0.0 and prior to version 42.0.4, if `pkcs12.serialize_key_and_certificates` is called with both a certificate whose public key did not match the provided private key and an `encryption_algorithm` with `hmac_hash` set (via `PrivateFormat.PKCS12.encryption_builder().hmac_hash(...)`, then a NULL pointer dereference would occur, crashing the Python process. This has been resolved in version 42.0.4, the first version in which a `ValueError` is properly raised.