CVE-2026-31979

himmelblaud-tasks: local privilege escalation via /tmp symlink attack on Kerberos ccache

State: Published
Severity: 8.8 High
Published: Mar 11, 2026
Updated: Mar 11, 2026
Reserved: Mar 10, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	8.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H	GitHub_M

Weaknesses

CWE-59 Improper Link Resolution Before File Access ('Link Following')

Affected Products

Product	Versions
himmelblauhimmelblau-idm	>= 1.0.0, < 2.3.8Affected >= 3.0.0-alpha, < 3.1.0Affected

References

https://github.com/himmelblau-idm/himmelblau/security/advisories/GHSA-44wm-q286-ghq3

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