GHSA-Q2X5-4XJX-C6P9

Vulnerability from github – Published: 2026-01-21 22:49 – Updated: 2026-01-22 15:41
VLAI?
Summary
Backstage has a Possible SSRF when reading from allowed URL's in `backend.reading.allow`
Details

Impact

The FetchUrlReader component, used by the catalog and other plugins to fetch content from URLs, followed HTTP redirects automatically. This allowed an attacker who controls a host listed in backend.reading.allow to redirect requests to internal or sensitive URLs that are not on the allowlist, bypassing the URL allowlist security control.

This is a Server-Side Request Forgery (SSRF) vulnerability that could allow access to internal resources, but it does not allow attackers to include additional request headers.

Patches

This vulnerability is fixed in @backstage/backend-defaults version 0.12.2, 0.13.2, 0.14.1, and 0.15.0. Users should upgrade to this version or later.

Workarounds

  • Restrict backend.reading.allow to only trusted hosts that you control and that do not issue redirects
  • Ensure allowed hosts do not have open redirect vulnerabilities
  • Use network-level controls to block access from Backstage to sensitive internal endpoints

References

Severity ?
3.5 (Low)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "@backstage/backend-defaults"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.12.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@backstage/backend-defaults"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.13.0"
            },
            {
              "fixed": "0.13.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@backstage/backend-defaults"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.14.0"
            },
            {
              "fixed": "0.14.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-24048"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-01-21T22:49:37Z",
    "nvd_published_at": "2026-01-21T23:15:53Z",
    "severity": "LOW"
  },
  "details": "### Impact\n\nThe `FetchUrlReader` component, used by the catalog and other plugins to fetch content from URLs, followed HTTP redirects automatically. This allowed an attacker who controls a host listed in `backend.reading.allow` to redirect requests to internal or sensitive URLs that are not on the allowlist, bypassing the URL allowlist security control.\n\nThis is a Server-Side Request Forgery (SSRF) vulnerability that could allow access to internal resources, but it does not allow attackers to include additional request headers.\n\n### Patches\n\nThis vulnerability is fixed in `@backstage/backend-defaults` version 0.12.2, 0.13.2, 0.14.1, and 0.15.0. Users should upgrade to this version or later.\n\n### Workarounds\n\n- Restrict `backend.reading.allow` to only trusted hosts that you control and that do not issue redirects\n- Ensure allowed hosts do not have open redirect vulnerabilities\n- Use network-level controls to block access from Backstage to sensitive internal endpoints\n\n### References\n\n- [OWASP SSRF Prevention Cheat Sheet](https://cheatsheetseries.owasp.org/cheatsheets/Server_Side_Request_Forgery_Prevention_Cheat_Sheet.html)",
  "id": "GHSA-q2x5-4xjx-c6p9",
  "modified": "2026-01-22T15:41:25Z",
  "published": "2026-01-21T22:49:37Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/backstage/backstage/security/advisories/GHSA-q2x5-4xjx-c6p9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-24048"
    },
    {
      "type": "WEB",
      "url": "https://github.com/backstage/backstage/commit/27f9061d24affd1b9212fe0abd476bfc3fbaedcb"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/backstage/backstage"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Backstage has a Possible SSRF when reading from allowed URL\u0027s in `backend.reading.allow`"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.