{"id":"CVE-2026-31957","aliases":["EUVD-2026-11321","GHSA-q746-m2wv-qh4v"],"status":"published","title":"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.","severity":{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.0057,"percentile":0.47655,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-1188"],"published":"2026-03-11T19:25:21Z","modified":"2026-10-28T02:30:50Z","products":[{"vendor":"himmelblau-idm","product":"himmelblau"}],"references":[{"url":"https://github.com/himmelblau-idm/himmelblau/security/advisories/GHSA-q746-m2wv-qh4v","tags":["x_refsource_CONFIRM","Mitigation","Vendor Advisory","advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31957.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31957","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-31957","title":"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.","status":"published","published":"2026-03-11T19:25:21.23Z","modified":"2026-03-12T20:00:41Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"critical","assessor":"cna"}],"cwes":["CWE-1188"],"updated_at":"2026-11-02T14:19:51.277563Z"}],"euvd":[{"id":"EUVD-2026-11321","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.","status":"published","published":"2026-03-11T19:25:21Z","modified":"2026-03-12T20:00:41Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T19:25:35.389351Z"}],"nvd":[{"id":"CVE-2026-31957","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.","status":"published","published":"2026-03-11T20:16:16.447Z","modified":"2026-06-17T10:34:50.363Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"critical","assessor":"secondary"}],"cwes":["CWE-1188"],"updated_at":"2026-11-02T14:12:08.98071Z"}],"osv":[{"id":"CVE-2026-31957","title":"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.","status":"published","published":"2026-03-11T19:25:21.23Z","modified":"2026-10-28T02:30:50.255615235Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-1188"],"updated_at":"2026-11-02T15:45:01.218144Z"}]}}