VulnerabilityPublished 17 Dec 2025

CVE-2025-44005: smallstep Step-CA · Improper Authentication

Affects smallstep Step-CASource CVE Database V5

Not known to be exploited · CVSS 10.0 Critical.

Data as of 26 Oct 2026, 08:30 UTC

CVSS 3.1 base score

10.0Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 9.0% chance of exploitation in 30 days – higher than 95% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Changed
Confidentiality: High
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 17 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
GitHubsmallstep/certificates`pkg:github/smallstep/certificates`Other threats	Affected =0.28.3 =0.28.4	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Immediate mitigation steps include: 1) Identifying and inventorying all Step-CA instances running versions 0.28.3 or 0.28.4 within the organization. 2) Restricting network access to Step-CA ACME and SCEP endpoints to trusted management networks or VPNs to reduce exposure. 3) Temporarily disabling ACME and SCEP provisioners if feasible until patches are released. 4) Monitoring logs for unusual certificate issuance requests or anomalies in the CA operations. 5) Implementing additional out-of-band authorization checks or manual approval workflows for certificate issuance where possible. 6) Preparing to deploy patches or upgrades as soon as they become available from smallstep. 7) Reviewing and tightening certificate trust policies and revoking any suspicious certificates issued during the vulnerable period. 8) Enhancing network segmentation and intrusion detection to detect exploitation attempts. These steps go beyond generic advice by focusing on limiting exposure of vulnerable components and adding compensating controls in the certificate issuance process.

Description

An attacker can bypass authorization checks and force a Step CA ACME or SCEP provisioner to create certificates without completing certain protocol authorization checks.

Impact

For European organizations, the impact of CVE-2025-44005 is severe. Organizations relying on Step-CA for internal or external PKI services risk unauthorized certificate issuance, which can undermine trust in their cryptographic infrastructure. Attackers could impersonate internal services, intercept sensitive communications, or escalate attacks using forged certificates. This can lead to data breaches, loss of confidentiality, and potential regulatory non-compliance under GDPR and other data protection laws. Critical sectors such as finance, healthcare, government, and telecommunications are particularly vulnerable due to their reliance on secure certificate-based authentication and encryption. The scope of impact is broad because the vulnerability requires no authentication and can be exploited remotely, potentially affecting any exposed Step-CA deployment. The lack of known exploits in the wild does not reduce the urgency, as public disclosure may prompt rapid weaponization by threat actors.

CWE-287Improper Authentication (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Libraries or Frameworks
Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V2.8.5 (opens in a new tab)
V2.8.4 (opens in a new tab)
V9.2.3 (opens in a new tab)
Attack patterns
Fake the Source of Data (opens in a new tab)
Utilizing REST's Trust in the System Resource to Obtain Sensitive Data (opens in a new tab)
Session Hijacking (opens in a new tab)
Token Impersonation (opens in a new tab)
Upload a Web Shell to a Web Server (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 24 Dec 2025, 17:05 UTC

WeaknessesCWE-287

Technical details

References

Community reviews

Related threats