Himmelblau's Name-Based Group Matching in `pam_allow_groups` Leads to Potential Security Bypass

{
  "id": "d516df84fb9b3da46a61f5e60e9a371187dec3910b2a650a811ed80a886e11cd",
  "url": "https://osv.dev/vulnerability/CVE-2025-49012",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Himmelblau's Name-Based Group Matching in `pam_allow_groups` Leads to Potential Security Bypass",
    "summary": "Himmelblau is an interoperability suite for Microsoft Azure Entra ID and Intune. Himmelblau versions 0.9.0 through 0.9.14 and 1.00-alpha are vulnerable to a privilege escalation issue when Entra ID group-based access restrictions are configured using group display names instead of object IDs. Starting in version 0.9.0, Himmelblau introduced support for specifying group names in the `pam_allow_groups` configuration option. However, Microsoft Entra ID permits the creation of multiple groups with the same `displayName` via the Microsoft Graph API—even by non-admin users, depending on tenant settings. As a result, a user could create a personal group with the same name as a legitimate access group (e.g., `\"Allow-Linux-Login\"`), add themselves to it, and be granted authentication or `sudo` rights by Himmelblau. Because affected Himmelblau versions compare group names by either `displayName` or by the immutable `objectId`, this allows bypassing access control mechanisms intended to restrict login to members of official, centrally-managed groups. This issue is fixed in Himmelblau version **0.9.15** and later. In these versions, group name matching in `pam_allow_groups` has been deprecated and removed, and only group `objectId`s (GUIDs) may be specified for secure group-based filtering. To mitigate the issue without upgrading, replace all entries in `pam_allow_groups` with the objectId of the target Entra ID group(s) and/or audit your tenant for groups with duplicate display names us",
    "evidence": "osv:CVE-2025-49012",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2025-49012",
      "aliases": [
        "CVE-2025-49012",
        "GHSA-gcxr-m95v-qcf7"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/himmelblau-idm/himmelblau",
              "type": "GIT",
              "events": [
                {
                  "introduced": "e0a9a019da5407b3f8f525570c83f6ae7a8bd2e2"
                },
                {
                  "fixed": "d6935b40d321125893da4a988084de4b55b3e11f"
                },
                {
                  "introduced": "baf3d8bcf373e488f55ec3ebd5a39632da0b1e65"
                },
                {
                  "fixed": "918577f6a8392a71d9d3d67f20962c372a0c01c6"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0.9.0"
                      },
                      {
                        "fixed": "0.9.15"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "= 1.0.0-alpha"
                      },
                      {
                        "last_affected": "= 1.0.0-alpha"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandaloneSingleVersion"
                  },
                  {
                    "range": [
                      {
                        "fixed": "918577f6a8392a71d9d3d67f20962c372a0c01c6"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "= 1.0.0-alpha",
            "0.9.14",
            "1.0.0-alpha",
            "0.9.13",
            "0.9.12",
            "0.9.11",
            "0.9.10",
            "0.9.9",
            "0.9.8",
            "0.9.7",
            "0.9.6",
            "0.9.5",
            "0.9.4",
            "0.9.3",
            "0.9.2",
            "0.9.1",
            "0.9.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-49012.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:48.947453865Z",
      "provider": "osv",
      "references": [
        "https://learn.microsoft.com/en-us/answers/questions/1035045/azure-ad-b2c-creates-groups-with-the-same-name-usi?utm_source=chatgpt.com",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/49xxx/CVE-2025-49012.json",
        "https://github.com/himmelblau-idm/himmelblau/security/advisories/GHSA-gcxr-m95v-qcf7",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-49012",
        "https://github.com/himmelblau-idm/himmelblau/issues/554",
        "https://github.com/himmelblau-idm/himmelblau/commit/918577f6a8392a71d9d3d67f20962c372a0c01c6"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-287"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/49xxx/CVE-2025-49012.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-49012",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 516956,
  "published_at": "2025-06-05T22:29:40.744+00:00"
}