CVE-2026-31979
Himmelblau-Idm Himmelblau 1.0.0 – 2.3.8
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HSummary
CVE-2026-31979 is a high-severity Link Following (CWE-59) vulnerability in Himmelblau-Idm Himmelblau. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Path Interception (T1034); ranked at the 10th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AC-6 (Least Privilege) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-31979 is a local privilege escalation vulnerability in Himmelblau, an interoperability suite for Microsoft Azure Entra ID and Intune, affecting versions prior to 3.1.0 and 2.3.8. The issue stems from the himmelblaud-tasks daemon, which runs as root and writes Kerberos cache files under the predictable path /tmp/krb5cc_<uid> without symlink protections. Since commit 87a51ee, PrivateTmp has been explicitly removed from the daemon's systemd hardening configuration, exposing it to the host's /tmp directory. Classified as CWE-59 (Improper Link Resolution Before File Access), it carries a CVSS v3.1 base score of 8.8 (AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H).
A local user with low privileges can exploit this vulnerability by creating symlinks in /tmp that point to arbitrary files. When the root himmelblaud-tasks daemon writes to the expected Kerberos cache file paths, it follows the symlinks, allowing the attacker to chown root-owned files or overwrite them with attacker-controlled content. Successful exploitation results in full local privilege escalation to root.
The vulnerability is addressed in Himmelblau releases 3.1.0 and 2.3.8. Additional details on the issue and remediation are available in the GitHub security advisory at https://github.com/himmelblau-idm/himmelblau/security/advisories/GHSA-44wm-q286-ghq3.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-11332
Vulnerability Data
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…
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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(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V15.4.2
Mitigating Controls (NIST 800-53 r5) AI
Proper enforcement of access authorizations on the resolved target resource stops a link from reaching an unintended object.
Least-privilege limits the damage an attacker can cause after following an unintended link.
Validating file-name inputs can reject or canonicalize names that resolve to links before access occurs.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require code to validate paths and avoid unsafe link following.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect link-following flaws before release.
Secure SDLC practices can mandate link-resolution checks and canonicalization before file access.
Application security requirements can explicitly require safe handling of symbolic links and path traversal.
Secure architecture principles include input validation and safe file-access design patterns.
Secure coding standards directly address canonicalization and symlink attacks during implementation.
Access-control rules can limit which files are reachable, reducing exposure to malicious links.