CVE-2026-30836: Github.com/smallstep/certificates Step-ca Has Unauthenticated Certificate Issuance Vulnerability
CRITICALCVE-2026-30836 is a CRITICAL (CVSS 10.0) step-ca has unauthenticated certificate issuance vulnerability (CWE-287: Improper Authentication) affecting Github.com/smallstep/certificates libraries in the Go ecosystem. The issue involves step-ca has unauthenticated certificate issuance via scep updatereq (messagetype=18). Remediation is available by upgrading affected packages to version 0.30.0.
CVE-2026-30836 at a Glance
Security Impact
CVSS: 10.0
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N).
How to Fix CVE-2026-30836
To remediate this vulnerability, upgrade all affected Github.com/smallstep/certificates dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade github.com/smallstep/certificates to 0.30.0Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for github.com/smallstep/certificatesHow to Check if You Are Affected
To determine whether your application is affected by CVE-2026-30836, inspect your project dependencies for Github.com/smallstep/certificates:
inspect dependencies for github.com/smallstep/certificatesAnalyze the terminal output to locate any version of Github.com/smallstep/certificates in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.30.0), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-287: Improper Authentication, where when an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. In Github.com/smallstep/certificates, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-30836 Affected Github.com/smallstep/certificates Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
github.com/smallstep/certificates
|
Go |
< 0.30.0
|
0.30.0
|
References
Frequently Asked Questions
What is CVE-2026-30836?
Which Github.com/smallstep/certificates versions are affected?
What version fixes CVE-2026-30836?
Is github.com/smallstep/certificates affected?
What is the CVSS score of CVE-2026-30836?
What CWE is associated with CVE-2026-30836?
How can I check Go dependencies for CVE-2026-30836?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-q4r8-xm5f-56gw",
"modified" : "2026-04-08T11:57:49Z",
"published" : "2026-03-19T16:27:53Z",
"aliases" : [ "CVE-2026-30836" ],
"summary" : "step-ca has Unauthenticated Certificate Issuance via SCEP UpdateReq (MessageType=18)",
"details" : "## Summary\n\nAn attacker can force a Step CA SCEP provisioner to create certificates without completing certain protocol authorization checks.\n\n## Details\n\nSCEP requests carry a message type. On receipt of a SCEP request, Step CA starts processing it by parsing its contents. Message types that were considered valid, but not explicitly supported in Step CA, would result in getting parsed successfully. While processing the parsed SCEP message, authorization logic would be skipped for the non-supported message types.\n\nAs a result, the request would be treated as authorized, bypassing the authorization checks normally enforced as part of the SCEP protocol and its implementation in Step CA.\n\nAuthorization webhooks and regular CA policies, such as allowed names and restrictions on certificate validity periods, remain in place.\n\n## Mitigations\n\nIf you are unable to upgrade to v0.30.0 or newer, the attack can be mitigated by (temporarily) disabling or removing SCEP provisioners, or restricting access to SCEP provisioners to trusted clients only.\n\n## Fix\n\nIn v0.30.0, additional validation was added to SCEP provisioners, so that they reject unsupported message types.\n\n## Acknowledgements\n\nThis issue was identified and reported by Prasanth Sundararajan.\n\n## Embargo List\n\nIf 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.\n\nStay safe, and thank you for helping us keep the ecosystem secure.\n\nIf you have urgent questions, please contact [security@smallstep.com](mailto:security@smallstep.com).",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/smallstep/certificates"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "0.30.0"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/smallstep/certificates/security/advisories/GHSA-q4r8-xm5f-56gw"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-30836"
}, {
"type" : "WEB",
"url" : "https://github.com/smallstep/certificates/commit/e6da031d5125cfd99fe9a26f74bb41e4dacca4ef"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/smallstep/certificates"
}, {
"type" : "WEB",
"url" : "https://github.com/smallstep/certificates/releases/tag/v0.30.0-rc7"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-287", "CWE-295" ],
"severity" : "CRITICAL",
"github_reviewed" : true,
"github_reviewed_at" : "2026-03-19T16:27:53Z",
"nvd_published_at" : "2026-03-19T21:17:09Z"
}
}