Backstage: Scaffolder action input authorization bypass

{
  "id": "16a0630e893f98c149705a70a9b11f2d140d45e17e1f02cbf51af522ec526348",
  "url": "https://osv.dev/vulnerability/GHSA-hmp2-4m7g-22cv",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Backstage: Scaffolder action input authorization bypass",
    "summary": "### Impact An authenticated user with access to affected Scaffolder templates could bypass configured action restrictions. Depending on integration credentials, this could grant unauthorized access to repositories and related source-control resources. ### Patches Patched in `@backstage/plugin-scaffolder-backend` version `4.1.0` ### Workarounds - Restrict affected Scaffolder actions to trusted users and configure source-control integrations with least-privilege credentials.",
    "evidence": "osv:GHSA-hmp2-4m7g-22cv",
    "products": [
      {
        "name": {
          "value": "@backstage/plugin-scaffolder-backend",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "3.3.1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "@backstage/plugin-scaffolder-backend",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "3.4.1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "@backstage/plugin-scaffolder-backend",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.0.3",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "@backstage/plugin-scaffolder-backend",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.1.0",
            "evidence": "/affected/3/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "GHSA-hmp2-4m7g-22cv",
      "aliases": [
        "CVE-2026-106503",
        "GHSA-hmp2-4m7g-22cv"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "3.3.1"
                }
              ]
            }
          ],
          "package": {
            "name": "@backstage/plugin-scaffolder-backend",
            "purl": "pkg:npm/%40backstage/plugin-scaffolder-backend",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-hmp2-4m7g-22cv/GHSA-hmp2-4m7g-22cv.json"
          }
        },
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "3.4.0"
                },
                {
                  "fixed": "3.4.1"
                }
              ]
            }
          ],
          "package": {
            "name": "@backstage/plugin-scaffolder-backend",
            "purl": "pkg:npm/%40backstage/plugin-scaffolder-backend",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-hmp2-4m7g-22cv/GHSA-hmp2-4m7g-22cv.json"
          }
        },
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "4.0.0"
                },
                {
                  "fixed": "4.0.3"
                }
              ]
            }
          ],
          "package": {
            "name": "@backstage/plugin-scaffolder-backend",
            "purl": "pkg:npm/%40backstage/plugin-scaffolder-backend",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-hmp2-4m7g-22cv/GHSA-hmp2-4m7g-22cv.json"
          }
        },
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "4.0.4"
                },
                {
                  "fixed": "4.1.0"
                }
              ]
            }
          ],
          "package": {
            "name": "@backstage/plugin-scaffolder-backend",
            "purl": "pkg:npm/%40backstage/plugin-scaffolder-backend",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-hmp2-4m7g-22cv/GHSA-hmp2-4m7g-22cv.json"
          }
        }
      ],
      "modified": "2026-10-07T18:15:12.169871159Z",
      "provider": "osv",
      "references": [
        "https://github.com/backstage/backstage/security/advisories/GHSA-hmp2-4m7g-22cv",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-106503",
        "https://github.com/backstage/backstage/commit/11c1384c0649b8ab26391c6a4e4f34b80ab0d188",
        "https://github.com/backstage/backstage/commit/a91ed72d540e80b62a73b39bb1563ff5018d52d1",
        "https://github.com/backstage/backstage/commit/e307e4f487103d815e484291b3fda778ab9983bf",
        "https://github.com/backstage/backstage",
        "https://github.com/backstage/backstage/releases/tag/v1.49.6",
        "https://github.com/backstage/backstage/releases/tag/v1.50.5",
        "https://github.com/backstage/backstage/releases/tag/v1.54.6"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-178",
          "CWE-284"
        ],
        "severity": "HIGH",
        "github_reviewed": true,
        "nvd_published_at": "2026-10-06T22:17:05Z",
        "github_reviewed_at": "2026-10-07T17:59:08Z"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-106503",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 97161,
  "published_at": "2026-10-07T17:59:08+00:00"
}