GHSA-WVP2-4QQP-4H3R

Vulnerability from github – Published: 2026-08-04 21:13 – Updated: 2026-08-04 21:13
VLAI
Summary
Ghost: Private IP filtering bypass to make server-side requests to internal services
Details

Impact

When making an external request, it is possible to bypass the IP filter that ensures the request isn't going to an internal service using an IPv6 literal which maps to a private IPv4 address.

Vulnerable versions

This vulnerability is present in Ghost from v6.0.9 up to v6.21.0.

Patches

v6.21.1 contains a fix for this issue.

How to update

For self-hosters using Docker, find Docker's official Ghost image here. Updating a Docker-based Ghost instance is documented here.

If your Ghost is a Ghost-CLI install see our documentation on updating it to the latest version here.

References

Ghost thanks l3tchupkt for disclosing this vulnerability responsibly.

For more information

If you have any questions or comments about this advisory, email us at security@ghost.org.

Severity
5.8 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Show details on source website
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 6.21.0"
      },
      "package": {
        "ecosystem": "npm",
        "name": "ghost"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.0.9"
            },
            {
              "fixed": "6.21.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-53944"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-184",
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-04T21:13:16Z",
    "nvd_published_at": "2026-06-24T19:17:11Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nWhen making an external request, it is possible to bypass the IP filter that ensures the request isn\u0027t going to an internal service using an IPv6 literal which maps to a private IPv4 address.\n\n### Vulnerable versions\n\nThis vulnerability is present in Ghost from v6.0.9 up to v6.21.0.\n\n### Patches\n\nv6.21.1 contains a fix for this issue.\n\n### How to update\n\nFor self-hosters using Docker, find [Docker\u0027s official Ghost image here](https://hub.docker.com/_/ghost). Updating a Docker-based Ghost instance [is documented here](https://docs.ghost.org/install/docker#updating-ghost). \n\nIf your Ghost is a Ghost-CLI install see our documentation on [updating it to the latest version here](https://docs.ghost.org/update). \n\n### References\n\nGhost thanks [l3tchupkt](http://github.com/l3tchupkt) for disclosing this vulnerability responsibly.\n\n### For more information\n\nIf you have any questions or comments about this advisory, email us at [security@ghost.org](mailto:security@ghost.org).",
  "id": "GHSA-wvp2-4qqp-4h3r",
  "modified": "2026-08-04T21:13:16Z",
  "published": "2026-08-04T21:13:16Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/TryGhost/Ghost/security/advisories/GHSA-wvp2-4qqp-4h3r"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53944"
    },
    {
      "type": "WEB",
      "url": "https://github.com/TryGhost/Ghost/pull/26749"
    },
    {
      "type": "WEB",
      "url": "https://github.com/TryGhost/Ghost/commit/9b7f2212970fade08ecbec543b405190471e38d4"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/TryGhost/Ghost"
    },
    {
      "type": "WEB",
      "url": "https://github.com/TryGhost/Ghost/releases/tag/v6.21.1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Ghost: Private IP filtering bypass to make server-side requests to internal services"
}



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Nomenclature

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  • 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.


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