Vulnerability · Published Apr 1, 2026 · Assigned by GitHub_M

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

Medium 6.3

In plain English

A medium-severity privilege mismanagement in himmelblau from himmelblau-idm. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 6% of all known vulnerabilities).

Severity (CVSS 3.1)6.3Medium

Exploit odds (30 days)0.2%top 94.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

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.

Affected products (as reported)

Vendor	Product	Versions
himmelblau-idm	himmelblau	>= 2.0.0-alpha, < 2.3.9>= 3.0.0-alpha, < 3.1.1

Weakness: CWE-269 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

References

https://github.com/himmelblau-idm/himmelblau/security/advisories/GHSA-v7xx-7mqc-g835 x_refsource_CONFIRM
https://github.com/himmelblau-idm/himmelblau/releases/tag/2.3.9 x_refsource_MISC
https://github.com/himmelblau-idm/himmelblau/releases/tag/3.1.1 x_refsource_MISC