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HimmelblauApplication · Himmelblau Idm

CVE-2026-31957

CRITICAL · 10.0 CVSS v3.1 Published 2026-03-11
Fix available
A fix is available. Upgrade to 3.1.0 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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. From 3.0.0 to before 3.1.0, if Himmelblau is deployed without a configured tenant domain in himmelblau.conf, authentication is not tenant-scoped. In this mode, Himmelblau can accept authentication attempts for arbitrary Entra ID domains by dynamically registering providers at runtime. This behavior is intended for initial/local bootstrap scenarios, but it can create risk in remote authentication environments. This vulnerability is fixed in 3.1.0.

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 · high confidence

Himmelblau versions 3.0.0 through before 3.1.0 allow authentication without tenant scoping when no tenant domain is configured in himmelblau.conf. In this misconfigured state, the software dynamically registers authentication providers at runtime and will accept authentication attempts for arbitrary Entra ID domains, enabling attackers to potentially authenticate against any Azure tenant.

MitigationConfigure a specific tenant domain in himmelblau.conf to scope authentication to your organization, and upgrade to Himmelblau 3.1.0 or later.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
HimmelblauApplication
Affected:< 3.1.0

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
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Himmelblau installation and version
    Locate the Himmelblau installation and determine the installed version number (for example, check package metadata, binary version info, or running 'himmelblau --version' if available)
    Affected if The installed version is 3.0.0 or any version before 3.1.0
  2. Locate himmelblau.conf configuration file
    Find the himmelblau.conf configuration file in the Himmelblau deployment (typical locations may include /etc/himmelblau/, the application directory, or the configuration directory of your deployment)
    Affected if The configuration file exists and is in use by your deployment
  3. Check for tenant domain configuration
    Open himmelblau.conf and search for any tenant domain setting (such as 'tenant_domain', 'tenant', or similar configuration keys that specify an Entra ID tenant identifier)
    Affected if No tenant domain is explicitly configured, or the relevant setting is absent or empty
  4. Verify runtime authentication provider behavior
    If possible, examine the authentication logs or test authentication flow to observe which Entra ID tenant the system attempts to authenticate against when no tenant domain is set
    Affected if The system accepts or attempts authentication against arbitrary Azure/Entra ID tenants rather than a single configured tenant
  5. Confirm affected configuration state
    Review the overall configuration to ensure a specific tenant domain is explicitly set and enforced for authentication
    Affected if The deployment relies on dynamic runtime provider registration without a fixed tenant scope, leaving authentication open to any Entra ID domain

Your environment is affected if you are running Himmelblau version 3.0.0 through before 3.1.0 AND the himmelblau.conf file lacks an explicitly configured tenant domain, allowing authentication attempts against arbitrary Entra ID tenants.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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
Upgrade available Upgrade to 3.1.0 or later
Fixed in 3.1.0
Interim mitigation

Configure a specific tenant domain in himmelblau.conf to scope authentication to your organization, and upgrade to Himmelblau 3.1.0 or later.

Recommended fix High confidence

3.1.0

  1. Upgrade Himmelblau to version 3.1.0 or later by installing the updated package from the official GitHub releases or repository

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

Fix this in Himmelblau Scoped from the published advisory
  • Consultation3.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,950
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,120.

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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

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-31957 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data