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Step CA Has Authorization Bypass in ACME and SCEP Provisioners

Critical severity GitHub Reviewed Published Dec 3, 2025 in smallstep/certificates • Updated Dec 3, 2025

Package

gomod github.com/smallstep/certificates (Go)

Affected versions

<= 0.28.4

Patched versions

0.29.0

Description

Summary

A security fix is now available for Step CA that resolves a vulnerability affecting deployments configured with ACME and/or SCEP provisioners.
All operators running these provisioners should upgrade to the latest release (v0.29.0) immediately.

The issue was discovered and disclosed by a research team during a security review. There is no evidence of active exploitation.

To limit exploitation risk during a coordinated disclosure window, we are withholding detailed technical information for now. A full write-up will be published in several weeks.

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.

Acknowledgements

This issue was identified and reported by Stephen Kubik of the Cisco Advanced Security Initiatives Group (ASIG)

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

References

@dopey dopey published to smallstep/certificates Dec 3, 2025
Published to the GitHub Advisory Database Dec 3, 2025
Reviewed Dec 3, 2025
Last updated Dec 3, 2025

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

EPSS score

Weaknesses

Missing Authentication for Critical Function

The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. Learn more on MITRE.

CVE ID

CVE-2025-44005

GHSA ID

GHSA-h8cp-697h-8c8p

Source code

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