# CVE-2026-26007: PyCA cryptography missing subgroup validation in SECT curves

Source: https://junglewise.ai/threats/cve-2026-26007-pyca-cryptography-missing-subgroup-validation-in-sect-curves  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-02-10. Updated: 2026-06-30  
License: CC BY 4.0 with a link back

CVE-2026-26007 · Severity: medium · CVSS 6.5 · Published 2026-02-10

The PyCA cryptography library, a widely used tool for securing Python applications, failed to properly validate certain types of security keys. This flaw could allow an attacker to trick a system into using a weak key, potentially revealing parts of a private encryption key or allowing the forgery of digital signatures. While the issue primarily affects less common 'binary' elliptic curves, it poses a risk to data confidentiality and the integrity of secure communications.

Technologies: [cryptography (PyPI)](https://junglewise.ai/threats/technologies/cryptography). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-26007 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-26007 being exploited in the wild.

**How severe is CVE-2026-26007?** Medium severity, with a CVSS score of 6.5, published 10 February 2026.

**Which products and versions are affected?** cryptography (PyPI) ECOSYSTEM:introduced=0,fixed=46.0.5.

**Is there a fix for CVE-2026-26007?** Yes. cryptography (PyPI): upgrade to 46.0.5 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-26007 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-26007?** Check whether you run cryptography (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- cryptography (PyPI): upgrade to 46.0.5 or later

  ```sh
  pip install "cryptography>=46.0.5"
  ```


## Technical details

The vulnerability exists in the public_key_from_numbers, load_der_public_key, and load_pem_public_key functions of the PyCA cryptography library. These functions fail to verify that a provided public key point belongs to the expected prime-order subgroup of the curve, specifically affecting SECT (binary) curves with a cofactor greater than 1. An attacker can provide a point from a small-order subgroup to perform a subgroup attack. In ECDH key exchange, this can leak the least significant bits of the victim's private key (private_key mod small_subgroup_order). In ECDSA, it allows for the forgery of signatures. The issue is resolved in version 46.0.5 by implementing mandatory subgroup validation for curves with cofactor > 1.

## Affected products

- PyCA cryptography < 46.0.5
- Red Hat Red Hat Enterprise Linux
- Red Hat Red Hat OpenShift AI

## Identifiers

- CVE-2026-26007
- GHSA-r6ph-v2qm-q3c2
- PYSEC-2026-2141

## Timeline

- 2026-02-10: disclosed
- 2026-02-10: patched: Fixed in version 46.0.5
- 2026-02-10: advisory

## References

- [https://github.com/pyca/cryptography/commit/0eebb9dbb6343d9bc1d91e5a2482ed4e054a6d8c](https://github.com/pyca/cryptography/commit/0eebb9dbb6343d9bc1d91e5a2482ed4e054a6d8c)
- [https://github.com/pyca/cryptography/security/advisories/GHSA-r6ph-v2qm-q3c2](https://github.com/pyca/cryptography/security/advisories/GHSA-r6ph-v2qm-q3c2)
- [http://www.openwall.com/lists/oss-security/2026/02/10/4](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-2026:10184)
- [https://access.redhat.com/errata/RHSA-2026:12176](https://access.redhat.com/errata/RHSA-2026:12176)
- [https://access.redhat.com/errata/RHSA-2026:13512](https://access.redhat.com/errata/RHSA-2026:13512)
- [https://access.redhat.com/errata/RHSA-2026:13545](https://access.redhat.com/errata/RHSA-2026:13545)

## Related threats

- [pyca cryptography improper certificate validation in Name Constraints](https://junglewise.ai/threats/cve-2026-69248-pyca-cryptography-improper-certificate-validation-in-name)
- [Pyca Cryptography exponential path-building in X.509 verification](https://junglewise.ai/threats/cve-2026-69249-pyca-cryptography-exponential-path-building-in-x-509-verification)
- [pyca cryptography Bleichenbacher oracle in PKCS#7 decryption](https://junglewise.ai/threats/cve-2026-69247-pyca-cryptography-bleichenbacher-oracle-in-pkcs-7-decryption)
- [PYSEC-2026-1284 - Vulnerable OpenSSL included in cryptography wheels](https://junglewise.ai/threats/cve-2024-12797-vulnerable-openssl-included-in-cryptography-wheels)
- [PYSEC-2026-1283 - Python Cryptography package vulnerable to Bleichenbacher timing oracle attack](https://junglewise.ai/threats/cve-2023-50782-python-cryptography-package-vulnerable-to-bleichenbacher-timing)