chore(deps): update dependency cryptography to v50 [security] - autoclosed

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
cryptography (changelog)	==46.0.3 → ==50.0.0

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

CVE-2026-26007 / GHSA-r6ph-v2qm-q3c2

More information

Details

Vulnerability Summary

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.

Credit

This vulnerability was discovered by:

• XlabAI Team of Tencent Xuanwu Lab
• Atuin Automated Vulnerability Discovery Engine

Severity

• CVSS Score: 8.2 / 10 (High)
• Vector String: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

References

• https://github.com/pyca/cryptography/security/advisories/GHSA-r6ph-v2qm-q3c2
• https://github.com/pyca/cryptography/commit/0eebb9dbb6343d9bc1d91e5a2482ed4e054a6d8c
• https://github.com/pyca/cryptography/releases/tag/46.0.5
• https://nvd.nist.gov/vuln/detail/CVE-2026-26007
• http://www.openwall.com/lists/oss-security/2026/02/10/4
• https://github.com/advisories/GHSA-r6ph-v2qm-q3c2

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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cryptography has incomplete DNS name constraint enforcement on peer names

CVE-2026-34073 / GHSA-m959-cc7f-wv43

More information

Details

Summary

In versions of cryptography prior to 46.0.5, 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 behavior resulted from a gap between RFC 5280 (which defines Name Constraint semantics) and RFC 9525 (which defines service identity semantics): put together, neither states definitively whether Name Constraints should be applied to peer names. To close this gap, cryptography now conservatively rejects any validation where the peer name would be rejected by a name constraint if it were a SAN instead.

In practice, exploitation of this bypass requires an uncommon X.509 topology, one that the Web PKI avoids because it exhibits these kinds of problems. Consequently, we consider this a medium-to-low impact severity.

See CVE-2025-61727 for a similar bypass in Go's crypto/x509.

Remediation

Users should upgrade to 46.0.6 or newer.

Attribution

Reporter: @​1seal

Severity

• CVSS Score: 1.7 / 10 (Low)
• Vector String: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U

References

• https://github.com/pyca/cryptography/security/advisories/GHSA-m959-cc7f-wv43
• https://nvd.nist.gov/vuln/detail/CVE-2026-34073
• https://github.com/pypa/advisory-database/tree/main/vulns/cryptography/PYSEC-2026-35.yaml
• https://github.com/advisories/GHSA-m959-cc7f-wv43

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Cryptography vulnerable to buffer overflow if non-contiguous buffers were passed to APIs

CVE-2026-39892 / GHSA-p423-j2cm-9vmq

More information

Details

If a non-contiguous buffer was passed to APIs which accepted Python buffers (e.g. Hash.update()), this could lead to buffer overflows. For example:

h = Hash(SHA256())
b.update(buf[::-1])

would read past the end of the buffer on Python >3.11

Severity

• CVSS Score: 6.9 / 10 (Medium)
• Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

References

• https://github.com/pyca/cryptography/security/advisories/GHSA-p423-j2cm-9vmq
• https://nvd.nist.gov/vuln/detail/CVE-2026-39892
• http://www.openwall.com/lists/oss-security/2026/04/08/12
• https://github.com/pypa/advisory-database/tree/main/vulns/cryptography/PYSEC-2026-36.yaml
• https://github.com/advisories/GHSA-p423-j2cm-9vmq

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Vulnerable OpenSSL included in cryptography wheels

GHSA-537c-gmf6-5ccf

More information

Details

pyca/cryptography's wheels include a statically linked copy of OpenSSL. The versions of OpenSSL included in wheels prior to cryptograph 48.01 are vulnerable to a security issue. More details about the vulnerability itself can be found in https://openssl-library.org/news/secadv/20260609.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.

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

• https://github.com/pyca/cryptography/security/advisories/GHSA-537c-gmf6-5ccf
• https://openssl-library.org/news/secadv/20260609.txt
• https://github.com/advisories/GHSA-537c-gmf6-5ccf

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing

CVE-2026-69247 / GHSA-g6cj-pr64-35w5

More information

Details

Summary

pkcs7_decrypt_der, pkcs7_decrypt_pem, and pkcs7_decrypt_smime reported the
outcome of decrypting a RecipientInfo's encryptedKey in several
distinguishable ways, one of which disclosed the exact length recovered from the
RSA operation. The same distinction was also observable by timing. An
application that decrypts attacker-supplied EnvelopedData and reflects the
outcome gives the attacker a Bleichenbacher oracle against the
content-encryption key.

Introduced in 44.0.0. Fixed in 50.0.0.

Details

Decryption ran as: RSA PKCS#1 v1.5 decrypt of encryptedKey → build an AES
cipher from the result → AES-CBC decrypt and PKCS#7 unpad. Each stage failed
differently, with no RFC 3218 mitigation:

1. invalid RSA padding → Decryption failed
2. valid padding, bad key length → Invalid key size (N) for AES., disclosing N
3. correct length, wrong key → Invalid padding bytes.
4. the real key → plaintext

Case 1 is reachable only where the linked library lacks implicit rejection:
OpenSSL 3.0 and 3.1, LibreSSL, and BoringSSL. On OpenSSL 3.2+, used in our wheels,
invalid padding instead returns a synthetic plaintext of
pseudorandom length, so the error channel does not distinguish conforming
ciphertexts.

Exploitation requires a service that auto-decrypts untrusted EnvelopedData
matching the victim certificate and answers adaptively at high volume, such as
an S/MIME gateway or mail filter.

Fix

Per RFC 3218, the content-encryption algorithm is now resolved before the
private key is used, so the expected key length is known in advance. If the RSA
decryption fails or recovers a key of the wrong length, a random key of the
expected length is substituted and decryption continues down an identical path.
All failures now report identically and perform the same work.

Not addressed by this fix

EnvelopedData does not authenticate its content. Tampering with
encryptedContent alone yields a CBC padding oracle that recovers plaintext at
roughly 256 queries per byte, without recovering any key, on every backend. This
is a property of PKCS#7 rather than of this implementation, cannot be fixed in
the library, and is now documented.

Credit

Reported by @​X1AOxiang.

Severity

• CVSS Score: 8.2 / 10 (High)
• Vector String: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

References

• https://github.com/pyca/cryptography/security/advisories/GHSA-g6cj-pr64-35w5
• https://github.com/pyca/cryptography/pull/15369
• https://github.com/pyca/cryptography/commit/53fccd93413a8d7f07d6d8999681f27b75cffa3f
• https://github.com/advisories/GHSA-g6cj-pr64-35w5

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Release Notes

pyca/cryptography (cryptography)

v50.0.0

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v49.0.0

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v48.0.1

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v48.0.0

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v47.0.0

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v46.0.7

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v46.0.6

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v46.0.5

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v46.0.4

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