# CVE-2026-31957

## Summary

- **CVE ID:** CVE-2026-31957
- **Severity:** CRITICAL
- **CVSS Score:** 10 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H)
- **CWE:** CWE-1188
- **Published:** Mar 11, 2026
- **Last Modified:** Mar 12, 2026

## Description

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.

## Affected Products

- himmelblau-idm — himmelblau (>= 3.0.0, < 3.1.0)

## References

- [CNA](https://github.com/himmelblau-idm/himmelblau/security/advisories/GHSA-q746-m2wv-qh4v)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.50%
- **EPSS Percentile:** 41.1

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-09._