CVE-2025-53013VulnerabilityPublished 26 Jun 2025Updated 20 Aug 2025

CVE-2025-53013: himmelblau · Improper Authentication

Affects himmelblauSource CVE Database V5

Not known to be exploited · CVSS 5.2 Medium : upgrade to 0.9.17 when convenient.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

5.2Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 13% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.9.17

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

Attack Vector: Physical
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: High
Availability: None

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

Attack Vector: Physical: The attack requires the attacker to physically touch or manipulate the vulnerable component. Physical interaction may be brief or persistent.
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: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
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 26 Jun 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 2026-10-25.

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

Upgrade himmelblau-idm/himmelblau to 0.9.17.

Affected software

Product	Affected	Fixed in
GitHubhimmelblau-idm/himmelblau`pkg:github/himmelblau-idm/himmelblau`Other threats	Affected <0.9.17 >=0.9.10	Fixed in 0.9.17

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

AI-suggested

To mitigate this vulnerability, European organizations should prioritize upgrading Himmelblau to version 0.9.17 or later, where the authentication logic flaw is corrected. For environments where immediate patching is not possible, administrators should disable Hello PIN authentication by setting `enable_hello = false` in `/etc/himmelblau/himmelblau.conf` to prevent exploitation. Additionally, organizations should enforce strict physical security controls to limit unauthorized local access to Linux hosts using Himmelblau. Monitoring and logging local authentication attempts can help detect suspicious activities exploiting this flaw. Network segmentation and limiting offline operation of critical systems can reduce exposure. Regular audits of authentication configurations and ensuring fallback authentication mechanisms are secure will further strengthen defenses. Finally, organizations should educate IT staff about this vulnerability and incorporate it into incident response plans to quickly address any exploitation attempts.

Description

Himmelblau is an interoperability suite for Microsoft Azure Entra ID and Intune. A vulnerability present in versions 0.9.10 through 0.9.16 allows a user to authenticate to a Linux host via Himmelblau using an *invalid* Linux Hello PIN, provided the host is offline. While the user gains access to the local system, Single Sign-On (SSO) fails due to the network being down and the inability to issue tokens (due to a failure to unlock the Hello key). The core issue lies in an incorrect assumption within the `acquire_token_by_hello_for_business_key` function: it was expected to return a `TPMFail` error for an invalid Hello key when offline, but instead, a preceding nonce request resulted in a `RequestFailed` error, leading the system to erroneously transition to an offline success state without validating the Hello key unlock. This impacts systems using Himmelblau for authentication when operating in an offline state with Hello PIN authentication enabled. Rocky Linux 8 (and variants) are not affected by this vulnerability. The problem is resolved in Himmelblau version 0.9.17. A workaround is available for users who cannot immediately upgrade. Disabling Hello PIN authentication by setting `enable_hello = false` in `/etc/himmelblau/himmelblau.conf` will mitigate the vulnerability.

Impact

For European organizations, this vulnerability poses a risk primarily to Linux hosts using Himmelblau for authentication with Hello PIN enabled, especially in scenarios where systems may operate offline. Unauthorized local access could lead to integrity breaches, such as unauthorized modification of system files or configurations, potentially undermining system trustworthiness. Although confidentiality impact is limited, the ability to bypass authentication locally without valid credentials can facilitate lateral movement or privilege escalation within internal networks. The failure of SSO in offline mode limits remote access risks but does not mitigate local exploitation. Organizations relying on Himmelblau for secure authentication in critical infrastructure, government, finance, or healthcare sectors may face increased risk of insider threats or physical access attacks exploiting this flaw. Since Rocky Linux 8 variants are unaffected, organizations using these distributions may have reduced exposure. The medium severity score suggests a moderate risk level, but the ease of exploitation in offline conditions and lack of required privileges elevate the concern for environments where physical or local access controls are weak or where devices are frequently disconnected from networks.

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

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 21 Aug 2025, 00:39 UTC

WeaknessesCWE-287

Technical details

References

Community reviews

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