CVE-2025-44005Network attack vector

Unauthorized certificate issuance via unvalidated provisioner tokens

Published Dec 17, 2025 · Updated Dec 17, 2025

Improper authentication in Smallstep step-ca 0.28.4 and earlier allows remote attackers to issue certificates via ACME or SCEP. The signing authorization path accepts a token claiming an ACME or SCEP provisioner, treats the request as authenticated, and skips those protocols' authorization checks. An ACME or SCEP provisioner must be configured and network-accessible; authorization webhooks and CA name and validity policies still constrain issued certificates.

CVSS severity10.0
Critical
EPSS probability9.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in Smallstep step-ca 0.28.4 and earlier allows remote attackers to issue certificates via ACME or SCEP. The signing authorization path accepts a token claiming an ACME or SCEP provisioner, treats the request as authenticated, and skips those protocols' authorization checks. An ACME or SCEP provisioner must be configured and network-accessible; authorization webhooks and CA name and validity policies still constrain issued certificates.

The record

CVE
CVE-2025-44005
Published
Dec 17, 2025
Updated
Dec 17, 2025
Vendor
Smallstep
Product
step-ca
Classifications
CWE-287, T1649
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 17, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 17, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.28.4
  2. Affected versionversion=v0.28.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Smallstep · step-caversion=0.28.4; version=v0.28.3

Published CVSS scores

10.0SmallstepCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
T1649Steal or Forge Authentication Certificates

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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