Cryptography.io: >> Cryptography >> 0.5 Security Vulnerabilities
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 victim computes the shared secret as S = [victim_private_key]P via ECDH, this leaks information about victim_private_key mod (small_subgroup_order). For curves with cofactor > 1, this reveals the least significant bits of the private key. When these weak public keys are used in ECDSA , it's easy to forge signatures on the small subgroup. Only SECT curves are impacted by this. This vulnerability is fixed in 46.0.5.
CVSS Score
6.5
EPSS Score
0.0
Published
2026-02-10
A flaw was found in the python-cryptography package. This issue may allow a remote attacker to decrypt captured messages in TLS servers that use RSA key exchanges, which may lead to exposure of confidential or sensitive data.
CVSS Score
7.5
EPSS Score
0.011
Published
2024-02-05
In the cryptography package before 3.3.2 for Python, certain sequences of update calls to symmetrically encrypt multi-GB values could result in an integer overflow and buffer overflow, as demonstrated by the Fernet class.
CVSS Score
9.1
EPSS Score
0.013
Published
2021-02-07
HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size.
CVSS Score
7.5
EPSS Score
0.017
Published
2017-03-27