Update dependency cryptography to v46 [SECURITY]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
cryptography (changelog)	^42.0.8 || ^43.0.0 || ^44.0.0 || ^45.0.0 → ^46.0.0

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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/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/advisories/GHSA-p423-j2cm-9vmq

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

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Release Notes

pyca/cryptography (cryptography)

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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v46.0.3

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v46.0.2

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v46.0.1

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v46.0.0

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