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

> Authenticated users with names matching privileged groups can escalate privileges via NSS name collision in himmelblau.

- **Severity:** Medium 6.3 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Apr 2026
- **Updated:** 4 Apr 2026
- **Also known as:** GHSA-v7xx-7mqc-g835, SUSE-SU-2026:21437-1, openSUSE-SU-2026:10483-1, openSUSE-SU-2026:20658-1

## 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 (Improper Privilege Management)

## Which versions are affected by CVE-2026-34397?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `himmelblau` | openSUSE:Tumbleweed | All versions | 2.3.9+git0.a9fd29b-1.1 |

Products: 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](https://insights.sbomify.com/CVE-2026-31957/): Himmelblau unset domain configuration can allow any-tenant authentication at first login for remote deployments (critical 10.0)
- [CVE-2026-31979](https://insights.sbomify.com/CVE-2026-31979/): himmelblaud-tasks: local privilege escalation via /tmp symlink attack on Kerberos ccache (high 8.8)
- [CVE-2025-54882](https://insights.sbomify.com/CVE-2025-54882/): Himmelblau's Kerberos credential cache collection is world readable (high 7.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34397 and fix it if it is affected.

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

Affected product: himmelblau-idm himmelblau. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-34397/ (Markdown: https://insights.sbomify.com/CVE-2026-34397/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34397
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34397
- OSV: https://osv.dev/vulnerability/CVE-2026-34397

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34397/
Summaries are generated and may contain mistakes; the official description above is the record.