Backstage: Improper URL validation in catalog entity placeholder resolution

{
  "id": "f5ea1655f70809c3f2f97f596f86ac3887c688c9a1f01cbd08e20d6d3def1bff",
  "url": "https://osv.dev/vulnerability/GHSA-qgvj-qcf8-xq73",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Backstage: Improper URL validation in catalog entity placeholder resolution",
    "summary": "### Impact An authenticated Backstage user could craft a catalog entity with placeholder directives that reference resources outside the entity's source repository. Under certain configurations, this could allow access to data not intended to be available to the user. ### Patches Patched in `@backstage/plugin-catalog-backend` version `3.9.1` ### Workarounds If you're not able to update immediately: - Limit the scope of integration credentials (e.g., GitHub tokens) to only the repositories that Backstage needs to access.",
    "evidence": "osv:GHSA-qgvj-qcf8-xq73",
    "products": [
      {
        "name": {
          "value": "@backstage/plugin-catalog-backend",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "3.9.1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "GHSA-qgvj-qcf8-xq73",
      "aliases": [
        "CVE-2026-106498",
        "GHSA-qgvj-qcf8-xq73"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "3.9.1"
                }
              ]
            }
          ],
          "package": {
            "name": "@backstage/plugin-catalog-backend",
            "purl": "pkg:npm/%40backstage/plugin-catalog-backend",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-qgvj-qcf8-xq73/GHSA-qgvj-qcf8-xq73.json"
          }
        }
      ],
      "modified": "2026-10-07T18:15:10.710570023Z",
      "provider": "osv",
      "references": [
        "https://github.com/backstage/backstage/security/advisories/GHSA-qgvj-qcf8-xq73",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-106498",
        "https://github.com/backstage/backstage/commit/0b0f6fc89b4eb4872c76a498abbe1dc65998bb6e",
        "https://github.com/backstage/backstage/commit/286bfc1f9cc3608a073b41016be302785be385d1",
        "https://github.com/backstage/backstage/commit/61a10f19926aeda7f4a32de48d733e6710584634",
        "https://github.com/backstage/backstage/commit/99729e925fd2bd40ba210022351a0ee6318e6197",
        "https://github.com/backstage/backstage/commit/e786ac309ed2d775daf2309393c015c43902d6f6",
        "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/v1.51.3",
        "https://github.com/backstage/backstage/releases/tag/v1.53.2",
        "https://github.com/backstage/backstage/releases/tag/v1.54.6"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-863",
          "CWE-918"
        ],
        "severity": "HIGH",
        "github_reviewed": true,
        "nvd_published_at": "2026-10-06T22:17:04Z",
        "github_reviewed_at": "2026-10-07T17:59:24Z"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-106498",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 97142,
  "published_at": "2026-10-07T17:59:24+00:00"
}