CVE-2026-31957: Himmelblau-IDM Himmelblau

Critical severity, CVSS 10.0. EPSS: 0.8% chance of exploitation in the next 30 days.

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: before 3.1.0 (fixed in 3.1.0)

Published 2026-03-11. Last modified 2026-06-17.