CVE-2026-24046: @backstage/backend defaults Path Traversal Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-rq6q-wr2q-7pgp",
  "modified" : "2026-01-22T15:41:18Z",
  "published" : "2026-01-21T22:36:36Z",
  "aliases" : [ "CVE-2026-24046" ],
  "summary" : "Backstage has a Possible Symlink Path Traversal in Scaffolder Actions",
  "details" : "### Impact\n\nMultiple Scaffolder actions and archive extraction utilities were vulnerable to symlink-based path traversal attacks. An attacker with access to create and execute Scaffolder templates could exploit symlinks to:\n\n1. **Read arbitrary files** via the `debug:log` action by creating a symlink pointing to sensitive files (e.g., `/etc/passwd`, configuration files, secrets)\n2. **Delete arbitrary files** via the `fs:delete` action by creating symlinks pointing outside the workspace\n3. **Write files outside the workspace** via archive extraction (tar/zip) containing malicious symlinks\n\nThis affects any Backstage deployment where users can create or execute Scaffolder templates.\n\n### Patches\n\nThis vulnerability is fixed in the following package versions:\n\n- `@backstage/backend-defaults` version 0.12.2, 0.13.2, 0.14.1, 0.15.0\n- `@backstage/plugin-scaffolder-backend` version 2.2.2, 3.0.2, 3.1.1\n- `@backstage/plugin-scaffolder-node` version 0.11.2, 0.12.3\n\nUsers should upgrade to these versions or later.\n\n### Workarounds\n\n- Follow the recommendation in the [Backstage Threat Model](https://backstage.io/docs/overview/threat-model#scaffolder) to limit access to creating and updating templates\n- Restrict who can create and execute Scaffolder templates using the permissions framework\n- Audit existing templates for symlink usage\n- Run Backstage in a containerized environment with limited filesystem access\n\n### References\n\n- [CWE-59: Improper Link Resolution Before File Access](https://cwe.mitre.org/data/definitions/59.html)\n- [OWASP Path Traversal](https://owasp.org/www-community/attacks/Path_Traversal)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@backstage/backend-defaults"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.12.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@backstage/backend-defaults"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.13.0"
      }, {
        "fixed" : "0.13.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@backstage/backend-defaults"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.14.0"
      }, {
        "fixed" : "0.14.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@backstage/plugin-scaffolder-backend"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.2.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@backstage/plugin-scaffolder-backend"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.0.0"
      }, {
        "fixed" : "3.0.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@backstage/plugin-scaffolder-backend"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.1.0"
      }, {
        "fixed" : "3.1.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@backstage/plugin-scaffolder-node"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.11.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@backstage/plugin-scaffolder-node"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.12.0"
      }, {
        "fixed" : "0.12.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/backstage/backstage/security/advisories/GHSA-rq6q-wr2q-7pgp"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-24046"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/backstage/backstage/commit/c641c147ab371a9a8a2f5f67fdb7cb9c97ef345d"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/backstage/backstage"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22", "CWE-59" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-21T22:36:36Z",
    "nvd_published_at" : "2026-01-21T23:15:53Z"
  }
}