CVE-2025-49012: Auth Bypass (CVSS 5.4)

Description

Himmelblau is an interoperability suite for Microsoft Azure Entra ID and Intune. Himmelblau versions 0.9.0 through 0.9.14 and 1.00-alpha are vulnerable to a privilege escalation issue when Entra ID group-based access restrictions are configured using group display names instead of object IDs. Starting in version 0.9.0, Himmelblau introduced support for specifying group names in the `pam_allow_groups` configuration option. However, Microsoft Entra ID permits the creation of multiple groups with the same `displayName` via the Microsoft Graph API—even by non-admin users, depending on tenant settings. As a result, a user could create a personal group with the same name as a legitimate access group (e.g., `"Allow-Linux-Login"`), add themselves to it, and be granted authentication or `sudo` rights by Himmelblau. Because affected Himmelblau versions compare group names by either `displayName` or by the immutable `objectId`, this allows bypassing access control mechanisms intended to restrict login to members of official, centrally-managed groups. This issue is fixed in Himmelblau version **0.9.15** and later. In these versions, group name matching in `pam_allow_groups` has been deprecated and removed, and only group `objectId`s (GUIDs) may be specified for secure group-based filtering. To mitigate the issue without upgrading, replace all entries in `pam_allow_groups` with the objectId of the target Entra ID group(s) and/or audit your tenant for groups with duplicate display names using the Microsoft Graph API.

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CVSS v3.1 Score

5.4

MEDIUM

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

Weakness Type (CWE)

CWE-287 Improper Authentication

References

Other References

https://github.com/himmelblau-idm/himmelblau/commit/918577f6a8392a71d9d3d67f20962c372a0c01c6 https://github.com/himmelblau-idm/himmelblau/issues/554 https://github.com/himmelblau-idm/himmelblau/security/advisories/GHSA-gcxr-m95v-qcf7 https://learn.microsoft.com/en-us/answers/questions/1035045/azure-ad-b2c-creates-groups-with-the-same-name-usi?utm_source=chatgpt.com

Frequently Asked Questions

What is CVE-2025-49012? +

Himmelblau is an interoperability suite for Microsoft Azure Entra ID and Intune. Himmelblau versions 0.9.0 through 0.9.14 and 1.00-alpha are vulnerable to a privilege escalation issue when Entra ID group-based access restrictions are configured using group display names instead of object IDs. Starting in version 0.9.0, Himmelblau introduced support for specifying group names in the `pam_allow_groups` configuration option. However, Microsoft Entra ID permits the creation of multiple groups with the same `displayName` via the Microsoft Graph API—even by non-admin users, depending on tenant settings. As a result, a user could create a personal group with the same name as a legitimate access group (e.g., `"Allow-Linux-Login"`), add themselves to it, and be granted authentication or `sudo` rights by Himmelblau. Because affected Himmelblau versions compare group names by either `displayName` or by the immutable `objectId`, this allows bypassing access control mechanisms intended to restrict login to members of official, centrally-managed groups. This issue is fixed in Himmelblau version **0.9.15** and later. In these versions, group name matching in `pam_allow_groups` has been deprecated and removed, and only group `objectId`s (GUIDs) may be specified for secure group-based filtering. To mitigate the issue without upgrading, replace all entries in `pam_allow_groups` with the objectId of the target Entra ID group(s) and/or audit your tenant for groups with duplicate display names using the Microsoft Graph API. It has a CVSS v3.1 base score of 5.4 (MEDIUM).

How severe is CVE-2025-49012? +

CVE-2025-49012 has a CVSS v3.1 score of 5.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2025-49012? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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