CVE-2026-31979 — himmelblaud-tasks: local privilege escalation via /tmp symlink attack on Kerberos ccache

Description (CNA)

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.

Affected (CNA)

Vendor / product	Versions
himmelblau-idm / himmelblau	affected >= 1.0.0, < 2.3.8; affected >= 3.0.0-alpha, < 3.1.0

CWE

CWE-59

References

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

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.