CVE-2026-45108: high-severity vulnerability in himmelblau-idm himmelblau
Himmelblau: Authentication Bypass via Cross-User Local Session Impersonation in Device Authorization Grant (DAG) Flow
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.4epss 0.2%
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.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L
Affected products
himmelblau-idm · himmelblauRelated CVEs — himmelblau-idm himmelblau
In the same product, most dangerous first.
CVE-2026-31957CRITICALHimmelblau unset domain configuration can allow any-tenant authentication at first login for remote deploymentsEPSS 0.5%CVE-2025-49012MEDIUMHimmelblau's Name-Based Group Matching in `pam_allow_groups` Leads to Potential Security BypassEPSS 0.4%CVE-2025-54882HIGHHimmelblau's Kerberos credential cache collection is world readableEPSS 0.2%CVE-2025-53013MEDIUMHimmelblau offline auth permits authentication with invalid Hello PINEPSS 0.2%CVE-2026-31979HIGHhimmelblaud-tasks: local privilege escalation via /tmp symlink attack on Kerberos ccacheEPSS 0.2%CVE-2025-24034LOWHimmelblau leaks credentials in the debug logEPSS 0.2%