Security Digest · Vulnerability record
CVE-2025-44005: Step CA Has Authorization Bypass in ACME and SCEP Provisioners
An attacker can bypass authorization checks and force a Step CA ACME or SCEP provisioner to create certificates without completing certain protocol authorization checks.
CVSS 10.0 Critical EPSS 9.1% · p95
Should you act?
High exploit likelihood
EPSS ranks it in the top 5% of all CVEs for likely exploitation in the next 30 days. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 9.1%, percentile 95: FIRST’s model estimates a 9.1% chance of exploitation activity in the next 30 days, higher than 95% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
github.com/smallstep/certificates(Go) <= 0.28.4, fixed in 0.29.0. Check your lockfile, including transitive dependencies.
What it is
An attacker can bypass authorization checks and force a Step CA ACME or SCEP provisioner to create certificates without completing certain protocol authorization checks.
From the GitHub advisory
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.
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Weakness type: CWE-287, CWE-306.
Product: github.com/smallstep/certificates (Go) · Assigned by: talos · Published: 2025-12-17
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Go | github.com/smallstep/certificates | <= 0.28.4 | 0.29.0 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| smallstep | Step-CA | 0.28.4, v0.28.3 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| talos | 3.1 | 10 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N |
| GitHub | 3.1 | 10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: changed (can affect other components)
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable yes, technical impact partial.
- FIRST EPSS (model of 2026-10-21): 9.09% probability of exploitation activity in the next 30 days; percentile 95.
Timeline
- — GitHub-reviewed advisory GHSA-h8cp-697h-8c8p published (critical)
- — CVE record last updated
- — CVE record published by talos
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-h8cp-697h-8c8p github.com
- CVE.org record CVE-2025-44005 cve.org
- NVD entry CVE-2025-44005 nvd.nist.gov
Other references from the CVE record and advisory
- talosintelligence.com talosintelligence.com
- github.com github.com
- talosintelligence.com talosintelligence.com
- github.com github.com