CVE-2026-45108: Himmelblau-IDM Himmelblau

High severity, CVSS 8.4. EPSS: 0.4% chance of exploitation in the next 30 days.

Himmelblau is an interoperability suite for Microsoft Azure Entra ID and Intune. From 2.0.0 to before 3.1.5 and 2.3.11, Himmelblau contained an authentication bypass vulnerability in the Device Authorization Grant (DAG) flow that allowed a user within the same Entra ID domain to obtain a local Unix session as another user by providing their own valid credentials. The vulnerability existed in the token_validate function, which validated domain aliases for legitimate multi-domain scenarios but failed to verify that the local part (username) of the authenticated user's UPN matched the requested account username. The function only compared domains, not the complete usernames. This vulnerability is fixed in 3.1.5 and 2.3.11.

Affected products

• Himmelblau-IDM Himmelblau: from 2.0.0, before 2.3.11 (fixed in 2.3.11); from 3.0.0-alpha, before 3.1.5 (fixed in 3.1.5)

Published 2026-05-27. Last modified 2026-06-17.