cryptography vulnerabilities

The cryptography library versions 38.0.0 through 42.0.4 contains a NULL pointer dereference vulnerability in pkcs12.serialize_key_and_certificates when a certificate does not match the private key and an encryption_algorithm with hmac_hash is set. This can crash the Python process.

The cryptography library for Python versions 45.0.0 through 46.0.6 contains a buffer overflow vulnerability. The issue occurs when a non-contiguous buffer is passed to APIs that accept Python buffers (e.g., Hash.update()). The flaw is fixed in version 46.0.7.

In the cryptography package for Python before version 3.3.2, sequences of update calls for symmetric encryption of multi-GB data can cause integer overflow and buffer overflow, as demonstrated with the Fernet class.

The cryptography package for Python in versions 45.0.0 through 48.0.0 has a vulnerability in certificate chain verification. If an intermediate constrained CA permits the DNS name foo.example.com, and the leaf certificate has a wildcard *.example.com, the verifier accepts the chain, allowing escape outside permitted names. Fixed in version 49.0.0.

cryptography, a cryptographic library for Python, versions 44.0.0 through 50.0.0, is vulnerable to a Bleichenbacher-style attack. Functions pkcs7_decrypt_der, pkcs7_decrypt_pem, and pkcs7_decrypt_smime reveal differences in decrypting encryptedKey, which can be exploited to decrypt the content-encryption key. Exploitation requires a service auto-decrypting untrusted EnvelopedData, e.g., S/MIME gateways. Fixed in version 50.0.0.

cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. Prior to version 46.0.6, DNS name constraints were only validated against SANs within child certificates, and not the "peer name" presented during each validation. Consequently, cryptography would allow a peer named bar.example.com to validate against a wildcard leaf certificate for *.example.com, even if the leaf's parent certificate (or upwards) contained an excluded subtree constraint for bar.example.com. This issue has been patched in version 46.0.6.

The cryptography library for Python before version 46.0.5 does not verify that a public key point belongs to the expected prime-order subgroup. This missing validation allows an attacker to provide a point from a small-order subgroup, leading to private key leakage in ECDH and signature forgery in ECDSA. Only SECT curves are affected.