Backstage: Secret-derived values may be exposed in scaffolder task logs

{
  "id": "fb51aa72bbefb8acfde77f183ff3a53d02447afc511c51a41ba280166ec49b58",
  "url": "https://osv.dev/vulnerability/GHSA-mfvq-x7vr-rgqg",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Backstage: Secret-derived values may be exposed in scaffolder task logs",
    "summary": "### Impact Deployments that configure sensitive `scaffolder.defaultEnvironment.secrets` and allow an attacker to create or modify Scaffolder templates are affected. A template author could cause secret-derived values used during template iteration to be persisted in task logs, exposing those values to users with access to the resulting task logs. ### Patches Patched in `@backstage/plugin-scaffolder-backend` version `4.1.0` ### Workarounds - Restrict permission to create or update Template entities to fully trusted parties, as recommended by the Backstage threat model. - If that restriction cannot be guaranteed, remove sensitive values from `scaffolder.defaultEnvironment.secrets` until a patched version is available. No complete workaround is known that preserves both untrusted template authoring and access to sensitive default-environment secrets.",
    "evidence": "osv:GHSA-mfvq-x7vr-rgqg",
    "products": [
      {
        "name": {
          "value": "@backstage/plugin-scaffolder-backend",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.1.0",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "GHSA-mfvq-x7vr-rgqg",
      "aliases": [
        "CVE-2026-106499",
        "GHSA-mfvq-x7vr-rgqg"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "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-mfvq-x7vr-rgqg/GHSA-mfvq-x7vr-rgqg.json"
          }
        }
      ],
      "modified": "2026-10-07T18:15:10.788059211Z",
      "provider": "osv",
      "references": [
        "https://github.com/backstage/backstage/security/advisories/GHSA-mfvq-x7vr-rgqg",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-106499",
        "https://github.com/backstage/backstage/commit/dc30fae2d96cb1606d36cc40b242f9b9e539bd70",
        "https://github.com/backstage/backstage",
        "https://github.com/backstage/backstage/releases/tag/v1.54.6"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-532"
        ],
        "severity": "MODERATE",
        "github_reviewed": true,
        "nvd_published_at": "2026-10-06T22:17:04Z",
        "github_reviewed_at": "2026-10-07T17:59:14Z"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-106499",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 97148,
  "published_at": "2026-10-07T17:59:14+00:00"
}