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VulnerabilityPublished

CVE-2026-31979: himmelblau · Link Following

Affects himmelblauSource CVE Database V5

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Not known to be exploited · CVSS 8.8 High : upgrade to 3.1.0 or 2.3.8 soon.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 3.1.0, 2.3.8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 11 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade himmelblau and himmelblau-idm/himmelblau to 3.1.0 or 2.3.8.

Affected software

ProductAffectedFixed in
himmelblau-idmhimmelblauAffected
  • >=3.0.0-alpha <3.1.0
Fixed in
  • 3.1.0
himmelblau-idmhimmelblauAffected
  • >=1.0.0 <2.3.8
Fixed in
  • 2.3.8
GitHubhimmelblau-idm/himmelblaupkg:github/himmelblau-idm/himmelblauOther threatsAffected
  • <2.3.8
  • <3.1.0
Fixed in
  • 2.3.8
  • 3.1.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2026-31979, organizations should immediately upgrade himmelblau to version 2.3.8 or 3.1.0 and later, where the vulnerability is fixed by restoring PrivateTmp sandboxing and adding symlink protections. Until upgrades can be applied, restrict local user access to systems running the vulnerable daemon, especially limiting shell or file system access to untrusted users. Implement strict file system permissions on /tmp to prevent unauthorized symlink creation, and monitor /tmp for suspicious symlink activity. Employ host-based intrusion detection systems (HIDS) to detect attempts to exploit symlink vulnerabilities. Review systemd service configurations to ensure PrivateTmp or equivalent sandboxing features are enabled for critical daemons. Additionally, audit Kerberos cache file handling and consider isolating the daemon in containers or virtual machines with limited local user access. Regularly review and apply security patches from the vendor and maintain an inventory of affected versions to prioritize remediation efforts.

Description

Himmelblau is an interoperability suite for Microsoft Azure Entra ID and Intune. Prior to 3.1.0 and 2.3.8, the himmelblaud-tasks daemon, running as root, writes Kerberos cache files under /tmp/krb5cc_<uid> without symlink protections. Since commit 87a51ee, PrivateTmp is explicitly removed from the tasks daemon's systemd hardening, exposing it to the host /tmp. A local user can exploit this via symlink attacks to chown or overwrite arbitrary files, achieving local privilege escalation. This vulnerability is fixed in 3.1.0 and 2.3.8.

References

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