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Improper AuthenticationWeakness · CWE-287

CVE-2025-49012

MEDIUM · 5.4 CVSS v3.1 Published 2025-06-05
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
60/100
Remediation priority · Elevated
Remotely reachable Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-287

The mechanism that verifies who a user is can be side-stepped or fooled, letting an attacker act as someone they're not. Everything built on top of that identity then becomes untrustworthy. Fixing it means hardening the full authentication flow, including edge cases, tokens, and secondary paths.

General guidance for the improper authentication class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

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

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch github.com →
Recommended fix High confidence

0.9.15

  1. Upgrade Himmelblau to version 0.9.15 or later
  2. Edit the Himmelblau configuration file (typically /etc/himmelblau.conf)
  3. Locate all pam_allow_groups configuration entries
  4. Replace any group display names with their corresponding Entra ID group objectIds (GUIDs)
  5. Verify the configuration syntax is correct and restart Himmelblau services
  6. Test authentication to ensure group-based access control works with objectId-based entries
Caveat Group name (displayName) matching in pam_allow_groups is deprecated and removed; only group objectIds (GUIDs) are now supported - existing configurations using display names will not work

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

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Peer-ranked notes from engineers who’ve handled CVE-2025-49012 in production — separate from our analysis above.

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