CVE-2026-31979: himmelblau-idm himmelblau Link Following

Vulnerability summary

CVE-2026-31979 is a high (CVSS 8.8) Link Following vulnerability in himmelblau-idm himmelblau. EPSS estimates a 0.20% chance of exploitation in the next 30 days, higher than 8.9% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 11-03-2026
   PublishedVulnerability first disclosed.
2. 11-03-2026
   Last modifiedVulnerability information updated.

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.

• CWE-59Improper Link Resolution Before File Access ('Link Following')The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.