How severe is GHSA-j7c9-79x7-8hpr?

GHSA-j7c9-79x7-8hpr has a CVSS score of 5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-j7c9-79x7-8hpr?

GHSA-j7c9-79x7-8hpr affects the following packages: github.com/smallstep/certificates (Go). Ecosystems affected: Go.

How do I fix GHSA-j7c9-79x7-8hpr?

Update github.com/smallstep/certificates to 0.29.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-j7c9-79x7-8hpr is resolved across your whole dependency graph.

How do I detect GHSA-j7c9-79x7-8hpr in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/smallstep/certificates. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-j7c9-79x7-8hpr if there is no patch (or I can't update yet)?

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 does O3 Security protect against GHSA-j7c9-79x7-8hpr?

O3 pinpoints whether GHSA-j7c9-79x7-8hpr is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-j7c9-79x7-8hpr actively exploited in the wild?

No public exploit code has been indexed for GHSA-j7c9-79x7-8hpr yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-j7c9-79x7-8hpr?

GHSA-j7c9-79x7-8hpr has an EPSS (Exploit Prediction Scoring System) score of 0.1%, placing it in the 3th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was GHSA-j7c9-79x7-8hpr published, and has it been updated?

GHSA-j7c9-79x7-8hpr was published on December 3, 2025 and was last updated on February 4, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

GHSA-j7c9-79x7-8hpr

MEDIUM

step-ca Has Improper Authorization Check for SSH Certificate Revocation

Also known asCVE-2025-66406GO-2025-4181

Published

Dec 3, 2025

Updated

Feb 4, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.1%probability of exploitation in next 30 days

Lower Risk3th percentile+0.11%

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.

Blast Radius

1 pkg affected

🐹github.com/smallstep/certificates

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Summary

An authorized attacker can bypass authorization checks and revoke any SSH certificate issued by Step CA by using a valid revocation token.

Details

Step CA users can obtain SSH certificates from a few provisioners. The SSHPOP provisioner allows revocation of the SSH certificate (preventing future certificate renewals) using a token. Due to a missing validity check, this token could be used to revoke any SSH certificate issued by the CA.

To create a token, an attacker must have access to the CA endpoint and a valid SSH certificate, meaning they were already authorized to obtain an SSH certificate. The attacker must also know the serial number of the certificate they want to revoke.

Impact

There is no way to mitigate this attack. It is recommended to update to v0.29.0 or newer.

Fix

In v0.29.0, the token validation logic was strengthened to bind each token to a specific SSH certificate serial number.

Acknowledgements

This issue was identified and reported by Gabriel Departout and Andy Russon, from AMOSSYS. This audit was sponsored by ANSSI (French Cybersecurity Agency) based on their Open-Source security audit program.

Embargo List

If your organization runs Step CA in production and would like advance, embargoed notification of future security updates, visit https://u.step.sm/disclosure to request inclusion on our embargo list.

Stay safe, and thank you for helping us keep the ecosystem secure.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/smallstep/certificates`	all versions	0.29.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/smallstep/certificates. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/smallstep/certificates to 0.29.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-j7c9-79x7-8hpr 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 pinpoints whether GHSA-j7c9-79x7-8hpr is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-j7c9-79x7-8hpr. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Summary An authorized attacker can bypass authorization checks and revoke any SSH certificate issued by Step CA by using a valid revocation token. ## Details Step CA users can obtain SSH certificates from a few provisioners. The SSHPOP provisioner allows revocation of the SSH certificate (preventing future certificate renewals) using a token. Due to a missing validity check, this token could be used to revoke any SSH certificate issued by the CA. To create a token, an attacker must have access to the CA endpoint and a valid SSH certificate, meaning they were already authorized to obtain a

O3 Security · Impact-Aware SCA

Is GHSA-j7c9-79x7-8hpr in your dependencies?

O3 detects GHSA-j7c9-79x7-8hpr across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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