cryptography Vulnerable to a Subgroup Attack Due to Missing Subgroup Validation for SECT Curves
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
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Python (PyPI) | cryptography | < 46.0.5 | 46.0.5 |
Referencias
- https://access.redhat.com/security/cve/CVE-2026-26007
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-26007.json
- http://www.openwall.com/lists/oss-security/2026/02/10/4
- https://access.redhat.com/errata/RHSA-2026:10184
- https://access.redhat.com/errata/RHSA-2026:12176
- https://access.redhat.com/errata/RHSA-2026:13512
- https://access.redhat.com/errata/RHSA-2026:13545
- https://access.redhat.com/errata/RHSA-2026:13553
- https://access.redhat.com/errata/RHSA-2026:13672
- https://access.redhat.com/errata/RHSA-2026:19355
- https://access.redhat.com/errata/RHSA-2026:21431
- https://access.redhat.com/errata/RHSA-2026:21517
- https://access.redhat.com/errata/RHSA-2026:22330
- https://access.redhat.com/errata/RHSA-2026:22993
- https://access.redhat.com/errata/RHSA-2026:2694
- https://access.redhat.com/errata/RHSA-2026:5168
- https://access.redhat.com/errata/RHSA-2026:5665
- https://access.redhat.com/errata/RHSA-2026:6308
- https://access.redhat.com/errata/RHSA-2026:6309
- https://access.redhat.com/errata/RHSA-2026:6497
- https://access.redhat.com/errata/RHSA-2026:6567
- https://access.redhat.com/errata/RHSA-2026:6568
- https://access.redhat.com/errata/RHSA-2026:7295
- https://github.com/pyca/cryptography/security/advisories/GHSA-r6ph-v2qm-q3c2
- https://bugzilla.redhat.com/show_bug.cgi?id=2438762
- https://github.com/pyca/cryptography/commit/0eebb9dbb6343d9bc1d91e5a2482ed4e054a6d8c
- https://nvd.nist.gov/vuln/detail/CVE-2026-26007
- https://github.com/pyca/cryptography
- https://github.com/pyca/cryptography/releases/tag/46.0.5
- Vector CVSS
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- Debilidad (CWE)
CWE-345- Plataforma
- Python (PyPI)
- Paquete
cryptography- Publicada
- 10.02.2026
- Actualizado
- 11.10.2026 15:17
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2026-2141 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-r6ph-v2qm-q3c2 - CC BY 4.0
Historial de vulnerabilidades: cryptography
Todas las vulnerabilidades publicadas de este paquete (Python (PyPI)), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.
- Entradas en total
- 24
- Primera → última
- 03.2017 08.2026
- Sin corrección
- 0
- Explotada en ataques
- 0
Distribución por gravedad
- Alta 12
- Media 7
- Baja 5
Divulgaciones por año
- 2017: 1
- 2018: 1
- 2019: 0
- 2020: 1
- 2021: 1
- 2022: 1
- 2023: 7
- 2024: 4
- 2025: 1
- 2026: 7
-
cryptography Vulnerable to a Subgroup Attack Due to Missing Subgroup Validation for SECT Curves esta entrada
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