CVE-2025-53013

CVE-2025-53013 is a medium-severity vulnerability with a CVSS 3.x base score of 5.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

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.

Frequently asked questions

What is CVE-2025-53013?
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.
How severe is CVE-2025-53013?
CVE-2025-53013 has a CVSS 3.x base score of 5.2, rated medium severity. It is exploitable over physical access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability none.
Is CVE-2025-53013 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-53013?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-53013 have an EU (EUVD) identifier?
Yes. CVE-2025-53013 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-19217.
When was CVE-2025-53013 published?
CVE-2025-53013 was published on 2025-06-26 and last updated on 2026-06-17.

References

Other CWE-287 (Improper Authentication) vulnerabilities

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