CVE-2026-34397 himmelblau: NSS fake-primary group lookup reintroduces name collision risk

What is CVE-2026-34397?

CVE-2026-34397 is a medium-severity vulnerability in himmelblau-idm himmelblau, published on 1 Apr 2026. 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. From versions 2.0.0-alpha to before 2.3.9 and 3.0.0-alpha to before 3.1.1, there is a conditional local privilege escalation vulnerability in an edge-case naming collision. Only authenticated himmelblau users whose mapped CN/short name exactly matches a privileged local group name (e.g., "sudo", "wheel", "docker", "adm") can cause the NSS module to resolve that group name to their fake primary group. If the system uses NSS results for group-based authorization decisions (sudo, polkit, etc.), this can grant the attacker the privileges of that group. This issue has been patched in versions 2.3.9 and 3.1.1.

Weakness: CWE-269

Which versions are affected by CVE-2026-34397?

It affects 1 product.

Products include Himmelblau-Idm Himmelblau.

How do I fix CVE-2026-34397?

Upgrade to a fixed version.

Is CVE-2026-34397 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34397 exists.

Other vulnerabilities in himmelblau-idm himmelblau

• CVE-2026-31957 Himmelblau unset domain configuration can allow any-tenant authentication at first login for remote deployments Critical 10.0
• CVE-2026-31979 himmelblaud-tasks: local privilege escalation via /tmp symlink attack on Kerberos ccache High 8.8
• CVE-2025-54882 Himmelblau's Kerberos credential cache collection is world readable High 7.1

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-v7xx-7mqc-g835, SUSE-SU-2026:21437-1, openSUSE-SU-2026:10483-1, openSUSE-SU-2026:20658-1.