REDHAT-BUG-2438762: High severity pypi/cryptography vulnerability
cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. Prior to 46.0.5, the publickeyfromnumbers (or EllipticCurvePublicNumbers.publickey()), EllipticCurvePublicNumbers.publickey(), loadderpublickey() and loadpempublickey() 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 = [victimprivatekey]P via ECDH, this leaks information about victimprivatekey mod (smallsubgrouporder). 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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
cryptographyto a version that resolves this vulnerability.Fixed in 46.0.5
Event History
Frequently Asked Questions
What is the severity of REDHAT-BUG-2438762?
The severity of REDHAT-BUG-2438762 is rated high with a score of 7.
How do I fix REDHAT-BUG-2438762?
To fix REDHAT-BUG-2438762, upgrade the cryptography package to version 46.0.5 or later.
What functions are affected by REDHAT-BUG-2438762?
REDHAT-BUG-2438762 affects the public_key_from_numbers, EllipticCurvePublicNumbers.public_key(), load_der_public_key(), and load_pem_public_key() functions.
What software is impacted by REDHAT-BUG-2438762?
The software impacted by REDHAT-BUG-2438762 is the Python package cryptography available on PyPI.
When was REDHAT-BUG-2438762 published?
REDHAT-BUG-2438762 was published on February 10, 2026.