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CVE-2026-26007

CVE-2026-26007 · cryptography Subgroup Attack Due to Missing Subgroup Validation for SECT Curves

This page contains facts from public vulnerability sources. Check the original advisory before updating.

This page shows selected source facts. See the linked advisories for the complete description and affected versions.

cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. Prior to 46.0.5, 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. This vulnerability is fixed in 46.0.5.

CVSS 8.2 · High · EPSS 0.4% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • cryptography

    Versions
    • < 46.0.5: Affected

    No fix published

  • python-cryptography Debian:12

    Versions
    • 38.0.4-3
    • 38.0.4-3+deb12u1
    • 38.0.4-4
    • 41.0.7-1
    • 41.0.7-2
    • 41.0.7-3
    • 41.0.7-4
    • 41.0.7-5
    • 42.0.5-1
    • 42.0.5-2
    • 43.0.0-1
    • 43.0.0-2
    • 43.0.0-3
    • 44.0.2-1
    • 44.0.2-2
    • 45.0.6-1
    • 45.0.6-1~exp1
    • 45.0.7-1
    • 46.0.1-1
    • 46.0.1-1~exp1
    • 46.0.5-1
    • 46.0.5-2
    • 46.0.6-1
    • 46.0.7-1
    • 47.0.0-1
    • 49.0.0-1
    • 49.0.0-1~exp1
    • 49.0.0-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-cryptography Debian:13

    Versions
    • 43.0.0-3
    Affected ranges
    • ECOSYSTEM: < 43.0.0-3+deb13u1

    Update to 43.0.0-3+deb13u1

  • python-cryptography Debian:14

    Versions
    • 43.0.0-3
    • 44.0.2-1
    • 44.0.2-2
    • 45.0.6-1
    • 45.0.6-1~exp1
    • 45.0.7-1
    • 46.0.1-1
    • 46.0.1-1~exp1
    Affected ranges
    • ECOSYSTEM: < 46.0.5-1

    Update to 46.0.5-1

  • cryptography PyPI

    Versions
    • 0.1
    • 0.2
    • 0.2.1
    • 0.2.2
    • 0.3
    • 0.4
    • 0.5
    • 0.5.1
    • 0.5.2
    • 0.5.3
    • 0.5.4
    • 0.6
    • 0.6.1
    • 0.7
    • 0.7.1
    • 0.7.2
    • 0.8
    • 0.8.1
    • 0.8.2
    • 0.9
    • 0.9.1
    • 0.9.2
    • 0.9.3
    • 1.0
    • 1.0.1
    • 1.0.2
    • 1.1
    • 1.1.1
    • 1.1.2
    • 1.2
    • 1.2.1
    • 1.2.2
    • 1.2.3
    • 1.3
    • 1.3.1
    • 1.3.2
    • 1.3.3
    • 1.3.4
    • 1.4
    • 1.5
    • 1.5.1
    • 1.5.2
    • 1.5.3
    • 1.6
    • 1.7
    • 1.7.1
    • 1.7.2
    • 1.8
    • 1.8.1
    • 1.8.2
    • 1.9
    • 2.0
    • 2.0.1
    • 2.0.2
    • 2.0.3
    • 2.1
    • 2.1.1
    • 2.1.2
    • 2.1.3
    • 2.1.4
    • 2.2
    • 2.2.1
    • 2.2.2
    • 2.3
    • 2.3.1
    • 2.4
    • 2.4.1
    • 2.4.2
    • 2.5
    • 2.6
    • 2.6.1
    • 2.7
    • 2.8
    • 2.9
    • 2.9.1
    • 2.9.2
    • 3.0
    • 3.1
    • 3.1.1
    • 3.2
    • 3.2.1
    • 3.3
    • 3.3.1
    • 3.3.2
    • 3.4
    • 3.4.1
    • 3.4.2
    • 3.4.3
    • 3.4.4
    • 3.4.5
    • 3.4.6
    • 3.4.7
    • 3.4.8
    • 35.0.0
    • 36.0.0
    • 36.0.1
    • 36.0.2
    • 37.0.0
    • 37.0.1
    • 37.0.2
    • 37.0.3
    • 37.0.4
    • 38.0.0
    • 38.0.1
    • 38.0.2
    • 38.0.3
    • 38.0.4
    • 39.0.0
    • 39.0.1
    • 39.0.2
    • 40.0.0
    • 40.0.1
    • 40.0.2
    • 41.0.0
    • 41.0.1
    • 41.0.2
    • 41.0.3
    • 41.0.4
    • 41.0.5
    • 41.0.6
    • 41.0.7
    • 42.0.0
    • 42.0.1
    • 42.0.2
    • 42.0.3
    • 42.0.4
    • 42.0.5
    • 42.0.6
    • 42.0.7
    • 42.0.8
    • 43.0.0
    • 43.0.1
    • 43.0.3
    • 44.0.0
    • 44.0.1
    • 44.0.2
    • 44.0.3
    • 45.0.0
    • 45.0.1
    • 45.0.2
    • 45.0.3
    • 45.0.4
    • 45.0.5
    • 45.0.6
    • 45.0.7
    • 46.0.0
    • 46.0.1
    • 46.0.2
    • 46.0.3
    • 46.0.4
    Affected ranges
    • ECOSYSTEM: < 46.0.5

    Update to 46.0.5

  • python-cryptography Ubuntu:Pro:16.04:LTS

    Versions
    • 1.0.1-1ubuntu1
    • 1.0.2-1
    • 1.1-1
    • 1.1.1-1
    • 1.1.1-1ubuntu1
    • 1.1.1-1ubuntu2
    • 1.1.1-1ubuntu3
    • 1.2.2-2
    • 1.2.3-1
    • 1.2.3-1ubuntu0.1
    • 1.2.3-1ubuntu0.2
    • 1.2.3-1ubuntu0.3
    • 1.2.3-1ubuntu0.3+esm1
    Affected ranges
    • ECOSYSTEM: < 1.2.3-1ubuntu0.3+esm3

    Update to 1.2.3-1ubuntu0.3+esm3

  • python-cryptography Ubuntu:Pro:18.04:LTS

    Versions
    • 1.9-1
    • 2.1.3-3
    • 2.1.4-1
    • 2.1.4-1build1
    • 2.1.4-1build2
    • 2.1.4-1ubuntu1
    • 2.1.4-1ubuntu1.1
    • 2.1.4-1ubuntu1.2
    • 2.1.4-1ubuntu1.3
    • 2.1.4-1ubuntu1.4
    • 2.1.4-1ubuntu1.4+esm1
    Affected ranges
    • ECOSYSTEM: < 2.1.4-1ubuntu1.4+esm3

    Update to 2.1.4-1ubuntu1.4+esm3

  • python-cryptography Ubuntu:Pro:20.04:LTS

    Versions
    • 2.6.1-3.1
    • 2.6.1-4
    • 2.6.1-4ubuntu1
    • 2.8-1ubuntu2
    • 2.8-2
    • 2.8-3
    • 2.8-3ubuntu0.1
    • 2.8-3ubuntu0.2
    • 2.8-3ubuntu0.3
    Affected ranges
    • ECOSYSTEM: < 2.8-3ubuntu0.3+esm2

    Update to 2.8-3ubuntu0.3+esm2

  • python-cryptography Ubuntu:22.04:LTS

    Versions
    • 3.3.2-1
    • 3.3.2-1build1
    • 3.4.8-1
    • 3.4.8-1ubuntu1
    • 3.4.8-1ubuntu2
    • 3.4.8-1ubuntu2.1
    • 3.4.8-1ubuntu2.2
    Affected ranges
    • ECOSYSTEM: < 3.4.8-1ubuntu2.3

    Update to 3.4.8-1ubuntu2.3

  • python-cryptography Ubuntu:24.04:LTS

    Versions
    • 38.0.4-4
    • 38.0.4-4ubuntu1
    • 41.0.7-3
    • 41.0.7-4build2
    • 41.0.7-4build3
    • 41.0.7-4ubuntu0.1
    Affected ranges
    • ECOSYSTEM: < 41.0.7-4ubuntu0.3

    Update to 41.0.7-4ubuntu0.3

  • python-cryptography Ubuntu:25.10

    Versions
    • 43.0.0-1ubuntu1
    Affected ranges
    • ECOSYSTEM: < 43.0.0-1ubuntu1.1

    Update to 43.0.0-1ubuntu1.1

Original sources

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