GHSA-r6ph-v2qm-q3c2 — cryptography
Fix: pyca/cryptography@0eebb9dGHSA-r6ph-v2qm-q3c2 is a CWE-345 vulnerability in cryptography. A fix is available for cryptography — see the affected versions and patch details below.
cryptography Vulnerable to a Subgroup Attack Due to Missing Subgroup Validation for SECT Curves
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-r6ph-v2qm-q3c2.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
cryptographyReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
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
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | cryptography | all versions | 46.0.5pip install --upgrade 'cryptography==46.0.5' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cryptography, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update cryptography to 46.0.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-r6ph-v2qm-q3c2 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-r6ph-v2qm-q3c2 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-r6ph-v2qm-q3c2. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This flaw, while difficult to exploit, would lead to a loss of integrity in the encrypted communication channel. Given that the cryptography package is a library, it is likely to be used in situations that do not require user interaction.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Ansible Automation Platform 2.5 for RHEL 8 | automation-controller-0:4.6.28-3.el8ap | RHSA-2026:13512 |
| Red Hat Enterprise Linux 8 | fence-agents-0:4.2.1-129.el8_10.25 | RHSA-2026:12176 |
| Red Hat Enterprise Linux 9 | fence-agents-0:4.10.0-98.el9_7.12 | RHSA-2026:13672 |
| Red Hat Enterprise Linux 9 | fence-agents-0:4.10.0-110.el9_8.2 | RHSA-2026:19355 |
| Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | fence-agents-0:4.10.0-43.el9_2.21 | RHSA-2026:22330 |
| Red Hat Enterprise Linux 9.4 Extended Update Support | fence-agents-0:4.10.0-62.el9_4.24 | RHSA-2026:21517 |
| Red Hat Enterprise Linux 9.6 Extended Update Support | fence-agents-0:4.10.0-86.el9_6.16 | RHSA-2026:21431 |
| Red Hat Ansible Automation Platform 2.5 | ansible-automation-platform-25/lightspeed-rhel8:1777403872 | RHSA-2026:13553 |
Frequently Asked Questions
Is GHSA-r6ph-v2qm-q3c2 in your dependencies?
O3 Security finds GHSA-r6ph-v2qm-q3c2 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.