Package Instance

cryptography Vulnerable to a Subgroup Attack Due to Missing Subgroup Validation for SECT Curves
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.

Vulnerable OpenSSL included in cryptography wheels
pyca/cryptography's wheels include a statically linked copy of OpenSSL. The versions of OpenSSL included in cryptography 2.5-41.0.3 is vulnerable to several security issues. More details about the vulnerabilities themselves can be found in https://www.openssl.org/news/secadv/20230908.txt.

If you are building cryptography source ("sdist") then you are responsible for upgrading your copy of OpenSSL. Only users installing from wheels built by the cryptography project (i.e., those distributed on PyPI) need to update their cryptography versions.

pyca/cryptography's wheels include vulnerable OpenSSL
pyca/cryptography's wheels include a statically linked copy of OpenSSL. The versions of OpenSSL included in cryptography 0.8-41.0.2 is vulnerable to several security issues. More details about the vulnerabilities themselves can be found in https://www.openssl.org/news/secadv/20230731.txt, https://www.openssl.org/news/secadv/20230719.txt, and https://www.openssl.org/news/secadv/20230714.txt.

If you are building cryptography source ("sdist") then you are responsible for upgrading your copy of OpenSSL. Only users installing from wheels built by the cryptography project (i.e., those distributed on PyPI) need to update their cryptography versions.

Python Cryptography package vulnerable to Bleichenbacher timing oracle attack
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.

Null pointer dereference in PKCS12 parsing
Issue summary: Processing a maliciously formatted PKCS12 file may lead OpenSSL
to crash leading to a potential Denial of Service attack

Impact summary: Applications loading files in the PKCS12 format from untrusted
sources might terminate abruptly.

A file in PKCS12 format can contain certificates and keys and may come from an
untrusted source. The PKCS12 specification allows certain fields to be NULL, but
OpenSSL does not correctly check for this case. This can lead to a NULL pointer
dereference that results in OpenSSL crashing. If an application processes PKCS12
files from an untrusted source using the OpenSSL APIs then that application will
be vulnerable to this issue.

OpenSSL APIs that are vulnerable to this are: PKCS12_parse(),
PKCS12_unpack_p7data(), PKCS12_unpack_p7encdata(), PKCS12_unpack_authsafes()
and PKCS12_newpass().

We have also fixed a similar issue in SMIME_write_PKCS7(). However since this
function is related to writing data we do not consider it security significant.

The FIPS modules in 3.2, 3.1 and 3.0 are not affected by this issue.