CVE-2026-31957
Himmelblau unset domain configuration can allow any-tenant authentication at first login for remote deployments
Description
Himmelblau is an interoperability suite for Microsoft Azure Entra ID and Intune. From 3.0.0 to before 3.1.0, if Himmelblau is deployed without a configured tenant domain in himmelblau.conf, authentication is not tenant-scoped. In this mode, Himmelblau can accept authentication attempts for arbitrary Entra ID domains by dynamically registering providers at runtime. This behavior is intended for initial/local bootstrap scenarios, but it can create risk in remote authentication environments. This vulnerability is fixed in 3.1.0.
INFO
Published Date :
March 11, 2026, 8:16 p.m.
Last Modified :
March 16, 2026, 7:39 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | [email protected] | ||||
| CVSS 3.1 | CRITICAL | MITRE-CVE |
Solution
- Update Himmelblau to version 3.1.0 or later.
- Configure a tenant domain in himmelblau.conf.
- Ensure authentication is tenant-scoped.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-31957.
| URL | Resource |
|---|---|
| https://github.com/himmelblau-idm/himmelblau/security/advisories/GHSA-q746-m2wv-qh4v | Mitigation Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-31957 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-31957
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-31957 vulnerability anywhere in the article.
-
Daily CyberSecurity
Weekly Threat Intelligence Briefing: Chrome Zero-Days, SolarWinds RCE, and a Surge in Critical PoCs
The Executive Summary Over the past seven days, our CVE Watchtower intercepted 1,388 new vulnerabilities, highlighting a relentless week in the cybersecurity landscape. While the sheer volume is high, ... Read more
The following table lists the changes that have been made to the
CVE-2026-31957 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Mar. 16, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:himmelblau-idm:himmelblau:*:*:*:*:*:*:*:* versions up to (excluding) 3.1.0 Added Reference Type GitHub, Inc.: https://github.com/himmelblau-idm/himmelblau/security/advisories/GHSA-q746-m2wv-qh4v Types: Mitigation, Vendor Advisory -
New CVE Received by [email protected]
Mar. 11, 2026
Action Type Old Value New Value Added Description Himmelblau is an interoperability suite for Microsoft Azure Entra ID and Intune. From 3.0.0 to before 3.1.0, if Himmelblau is deployed without a configured tenant domain in himmelblau.conf, authentication is not tenant-scoped. In this mode, Himmelblau can accept authentication attempts for arbitrary Entra ID domains by dynamically registering providers at runtime. This behavior is intended for initial/local bootstrap scenarios, but it can create risk in remote authentication environments. This vulnerability is fixed in 3.1.0. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Added CWE CWE-1188 Added Reference https://github.com/himmelblau-idm/himmelblau/security/advisories/GHSA-q746-m2wv-qh4v