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

High 8.8 Published 11 Mar 2026 Updated 11 Mar 2026

A local attacker can exploit a symlink vulnerability in the himmelblaud-tasks daemon to overwrite arbitrary files and escalate privileges to root.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2026-31979?

CVE-2026-31979 is a high-severity path traversal vulnerability in himmelblau-idm himmelblau, published on 11 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official 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.

Weakness: CWE-59

Which versions are affected by CVE-2026-31979?

It affects 1 product.

Linux distribution packages (1)

himmelblau openSUSE:Tumbleweed All versions 2.3.8+git0.dec3693-1.1

Products include Himmelblau-Idm Himmelblau.

How do I fix CVE-2026-31979?

Upgrade to a fixed version.

Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.

Is CVE-2026-31979 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-31979 exists.

Sources

Also known as GHSA-44wm-q286-ghq3, openSUSE-SU-2026:10328-1.