# CVE-2025-53013: Himmelblau offline auth permits authentication with invalid Hello PIN

> An attacker can bypass authentication on offline Linux hosts using Himmelblau by providing an invalid Hello PIN, gaining local system access.

- **Severity:** Medium 5.2 (`CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 Jun 2025
- **Updated:** 20 Aug 2025
- **Also known as:** GHSA-j93j-pwm6-p97j, openSUSE-SU-2025:15229-1

## What is CVE-2025-53013?

CVE-2025-53013 is a medium-severity authentication bypass vulnerability in himmelblau-idm himmelblau, published on 26 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2025-53013?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `himmelblau` | openSUSE:Tumbleweed | All versions | 0.9.17+git.0.4a97692-1.1 |

## How do I fix CVE-2025-53013?

Upgrade to a fixed version.

## Is CVE-2025-53013 being exploited?

There is no known exploitation of CVE-2025-53013 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-53013 and fix it if it is affected.

What it is: CVE-2025-53013 is a medium-severity authentication bypass vulnerability in himmelblau-idm himmelblau, published on 26 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-53013 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-2025-53013/ (Markdown: https://insights.sbomify.com/CVE-2025-53013/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-53013
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-53013
- OSV: https://osv.dev/vulnerability/CVE-2025-53013

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-53013/
Summaries are generated and may contain mistakes; the official description above is the record.