How severe is CVE-2026-31957?

CVE-2026-31957 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-31957 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (39th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-31957?

CVE-2026-31957 affects Himmelblau-idm Himmelblau. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-31957?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-31957 have an EU (EUVD) identifier?

Yes. CVE-2026-31957 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-11321.

When was CVE-2026-31957 published?

CVE-2026-31957 was published on 2026-03-11 and last updated on 2026-06-17.

CVE-2026-31957

CVE-2026-31957 is a critical-severity vulnerability in Himmelblau-idm Himmelblau with a CVSS 3.x base score of 10.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1188.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
EPSS exploit prediction: 1% (39th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-11321
Weakness: CWE-1188
Affected product: Himmelblau-idm Himmelblau
Published: 2026-03-11
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-31957?: 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.
How severe is CVE-2026-31957?: CVE-2026-31957 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-31957 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (39th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-31957?: CVE-2026-31957 affects Himmelblau-idm Himmelblau. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-31957?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-31957 have an EU (EUVD) identifier?: Yes. CVE-2026-31957 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-11321.
When was CVE-2026-31957 published?: CVE-2026-31957 was published on 2026-03-11 and last updated on 2026-06-17.

References

https://github.com/himmelblau-idm/himmelblau/security/advisories/GHSA-q746-m2wv-qh4v

Affected products (1)

cpe:2.3:a:himmelblau-idm:himmelblau:*:*:*:*:*:*:*:*

More vulnerabilities in Himmelblau-idm Himmelblau

CVE-2026-31979 — High (CVSS 8.8): Himmelblau is an interoperability suite for Microsoft Azure Entra ID and Intune. Prior to 3.1.0 and 2.3.8, the…
CVE-2025-54882 — High (CVSS 7.1): Himmelblau is an interoperability suite for Microsoft Azure Entra ID and Intune. In versions 0.8.0 through 0.9.21 and…
CVE-2026-34397 — Medium (CVSS 6.3): Himmelblau is an interoperability suite for Microsoft Azure Entra ID and Intune. From versions 2.0.0-alpha to before…

All CVEs affecting Himmelblau-idm Himmelblau →

Other CWE-1188 (Insecure Default Initialization of Resource) vulnerabilities

CVE-2025-41672 — Critical (CVSS 10.0): A remote unauthenticated attacker may use default certificates to generate JWT Tokens and gain full access to the tool…
CVE-2024-0001 — Critical (CVSS 10.0): A condition exists in FlashArray Purity whereby a local account intended for initial array configuration remains active…
CVE-2024-2912 — Critical (CVSS 10.0): An insecure deserialization vulnerability exists in the BentoML framework, allowing remote code execution (RCE) by…
CVE-2021-34795 — Critical (CVSS 10.0): Multiple vulnerabilities in the web-based management interface of the Cisco Catalyst Passive Optical Network (PON)…
CVE-2017-7964 — Critical (CVSS 10.0): Zyxel WRE6505 devices have a default TELNET password of 1234 for the root and admin accounts, which makes it easier for…
CVE-2026-44109 — Critical (CVSS 9.8): OpenClaw before 2026.4.15 contains an authentication bypass vulnerability in Feishu webhook and card-action validation…

Browse all CWE-1188 (Insecure Default Initialization of Resource) vulnerabilities →