CVE-2026-34397Public exploit

Privilege escalation via fake-primary group name collision

Published Apr 1, 2026 · Updated Apr 1, 2026

Privilege escalation in Himmelblau 2.0.0-alpha through 2.3.8 and 3.0.0-alpha through 3.1.0 allows local users to gain group privileges. The NSS get_entry_by_name path maps a short group name to a user UPN and returns the user's fake primary group without applying its name-equality guard. Exploitation requires an authenticated user with a short name matching a privileged local group, NSS group lookup enabled, and an authorization consumer that trusts the result.

CVSS severity6.3
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege escalation in Himmelblau 2.0.0-alpha through 2.3.8 and 3.0.0-alpha through 3.1.0 allows local users to gain group privileges. The NSS get_entry_by_name path maps a short group name to a user UPN and returns the user's fake primary group without applying its name-equality guard. Exploitation requires an authenticated user with a short name matching a privileged local group, NSS group lookup enabled, and an authorization consumer that trusts the result.

The record

CVE
CVE-2026-34397
Published
Apr 1, 2026
Updated
Apr 1, 2026
Vendor
Himmelblau
Product
Himmelblau
Classifications
CWE-269, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 2.0.0-alpha, < 2.3.9
  2. Affected versionversion=>= 3.0.0-alpha, < 3.1.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Himmelblau · Himmelblauversion=>= 2.0.0-alpha, < 2.3.9; version=>= 3.0.0-alpha, < 3.1.1

Published CVSS scores

7.0NIST NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
6.3GitHub, Inc.CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-269Improper Privilege Management
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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