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CVE-2026-45108

Full vulnerability record from the local CVENow database.

Description

Himmelblau is an interoperability suite for Microsoft Azure Entra ID and Intune. From 2.0.0 to before 3.1.5 and 2.3.11, Himmelblau contained an authentication bypass vulnerability in the Device Authorization Grant (DAG) flow that allowed a user within the same Entra ID domain to obtain a local Unix session as another user by providing their own valid credentials. The vulnerability existed in the token_validate function, which validated domain aliases for legitimate multi-domain scenarios but failed to verify that the local part (username) of the authenticated user's UPN matched the requested account username. The function only compared domains, not the complete usernames. This vulnerability is fixed in 3.1.5 and 2.3.11.

Severity
HIGH
CVSS score
8.4 (v3.1)
Vulnerability status
Deferred
Source identifier
Published
2026-05-27 20:16:38.550000
Last modified
2026-10-26 11:10:00.157000
View original CVE JSON
{
  "id": "CVE-2026-45108",
  "sourceIdentifier": "[email protected]",
  "published": "2026-05-27T20:16:38.550",
  "lastModified": "2026-10-26T11:10:00.157",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Himmelblau is an interoperability suite for Microsoft Azure Entra ID and Intune. From 2.0.0 to before 3.1.5 and 2.3.11, Himmelblau contained an authentication bypass vulnerability in the Device Authorization Grant (DAG) flow that allowed a user within the same Entra ID domain to obtain a local Unix session as another user by providing their own valid credentials. The vulnerability existed in the token_validate function, which validated domain aliases for legitimate multi-domain scenarios but failed to verify that the local part (username) of the authenticated user's UPN matched the requested account username. The function only compared domains, not the complete usernames. This vulnerability is fixed in 3.1.5 and 2.3.11."
    },
    {
      "lang": "es",
      "value": "Himmelblau es una suite de interoperabilidad para Microsoft Azure Entra ID e Intune. Desde la versión 2.0.0 hasta antes de la 3.1.5 y la 2.3.11, Himmelblau contenía una vulnerabilidad de omisión de autenticación en el flujo de Device Authorization Grant (DAG) que permitía a un usuario dentro del mismo dominio de Entra ID obtener una sesión Unix local como otro usuario al proporcionar sus propias credenciales válidas. La vulnerabilidad existía en la función token_validate, que validaba alias de dominio para escenarios legítimos de múltiples dominios, pero no verificaba que la parte local (nombre de usuario) del UPN del usuario autenticado coincidiera con el nombre de usuario de la cuenta solicitada. La función solo comparaba dominios, no los nombres de usuario completos. Esta vulnerabilidad está corregida en las versiones 3.1.5 y 2.3.11."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "himmelblau-idm",
          "product": "himmelblau",
          "versions": [
            {
              "version": ">= 2.0.0, < 2.3.11",
              "status": "affected"
            },
            {
              "version": ">= 3.0.0-alpha, < 3.1.5",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L",
          "baseScore": 8.4,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "HIGH",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "CHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "LOW"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 6.0
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-05-28T13:54:48.811361Z",
          "id": "CVE-2026-45108",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-863"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/himmelblau-idm/himmelblau/security/advisories/GHSA-pmxh-j4r6-88mv",
      "source": "[email protected]"
    }
  ]
}