UBUNTU-CVE-2026-26007

Advisory lineage Upstream: 1 Downstream: 3
Upstream
CVE-2026-26007
Published: 10 Feb 2026, 22:17
Last modified:20 Jul 2026, 16:19

Vulnerability Summary

Overall Risk (default)
medium
33/100
CVSS Score
8.2 HIGH
4.0 (osv_ubuntu)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

10 Feb 2026, 22:17
Published
Vulnerability first disclosed
20 Jul 2026, 16:19
Last Modified
Vulnerability information updated

Description

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 Metrics

  • v4.0•HIGH•Score: 8.2CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
  • v3.1•HIGH•Score: 7.4CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected Systems

  • ubuntu•python-cryptography

    all | all | all | all | all | < 1.2.3-1ubuntu0.3+esm3 | < 2.1.4-1ubuntu1.4+esm3 | < 2.8-3ubuntu0.3+esm2 | < 3.4.8-1ubuntu2.3 | < 41.0.7-4ubuntu0.3 | < 43.0.0-1ubuntu1.1

References (6)