# CVE-2025-49012: Himmelblau's Name-Based Group Matching in `pam_allow_groups` Leads to Potential Security Bypass

> Attackers can bypass login restrictions by creating Entra ID groups with duplicate display names, gaining unauthorized access or sudo privileges.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 5 Jun 2025
- **Updated:** 9 Jun 2025
- **Also known as:** GHSA-gcxr-m95v-qcf7

## What is CVE-2025-49012?

CVE-2025-49012 is a medium-severity authentication bypass vulnerability in himmelblau-idm himmelblau, published on 5 Jun 2025. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2025-49012?


## How do I fix CVE-2025-49012?

No fix has been published for CVE-2025-49012 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-49012 being exploited?

There is no known exploitation of CVE-2025-49012 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-49012 and fix it if it is affected.

What it is: CVE-2025-49012 is a medium-severity authentication bypass vulnerability in himmelblau-idm himmelblau, published on 5 Jun 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-49012 in the wild and no public exploit code.

Affected product: himmelblau-idm himmelblau. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-49012/ (Markdown: https://insights.sbomify.com/CVE-2025-49012/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-49012
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-49012
- OSV: https://osv.dev/vulnerability/CVE-2025-49012

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From sbomify Insights: https://insights.sbomify.com/CVE-2025-49012/
Summaries are generated and may contain mistakes; the official description above is the record.