himmelblau up to 0.9.16 himmelblau.conf acquire_token_by_hello_for_business_key improper authentication

Summaryinfo

A vulnerability was found in himmelblau up to 0.9.16. It has been classified as critical. This affects the function acquire_token_by_hello_for_business_key of the file /etc/himmelblau/himmelblau.conf. Performing a manipulation results in improper authentication. This vulnerability is known as CVE-2025-53013. The attack may be carried out on the physical device. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in himmelblau up to 0.9.16. It has been classified as critical. This affects the function acquire_token_by_hello_for_business_key of the file /etc/himmelblau/himmelblau.conf. The manipulation with an unknown input leads to a improper authentication vulnerability. CWE is classifying the issue as CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2025-53013 since 06/24/2025. The exploitability is told to be easy. An attack has to be approached locally. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 306681 (SUSE SLED15 / SLES15 Security Update : himmelblau (SUSE-SU-2026:1361-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 0.9.17 eliminates this vulnerability. Applying the patch 64b03739f1d5ee472b1cff3ed20ed9af1c65a6f8 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (306681) and EUVD (EUVD-2025-19217). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

• himmelblau

Version

• 0.9.0
• 0.9.1
• 0.9.2
• 0.9.3
• 0.9.4
• 0.9.5
• 0.9.6
• 0.9.7
• 0.9.8
• 0.9.9
• 0.9.10
• 0.9.11
• 0.9.12
• 0.9.13
• 0.9.14
• 0.9.15
• 0.9.16

License

• open-source

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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