GHSA-G366-23FW-GGP6

Vulnerability from github – Published: 2026-08-04 21:25 – Updated: 2026-08-04 21:25
VLAI
Summary
Ghost: Mobiledoc image-size fetch SSRF
Details

Impact

When re-rendering posts, Ghost would refetch missing image dimensions by issuing an outbound HTTP request to the URL stored on an image card — without restricting that URL to trusted image hosts. An authenticated staff user able to create or edit posts could therefore point an image card at an attacker-chosen host and cause the Ghost server to request it on their behalf, including hosts on internal networks or cloud instance metadata endpoints that would not normally be reachable from the public internet.

Vulnerable versions

This vulnerability is present in Ghost from v6.19.3 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.

For more information

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

Severity
5.4 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Show details on source website
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c 6.21.1"
      },
      "package": {
        "ecosystem": "npm",
        "name": "ghost"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.19.4"
            },
            {
              "fixed": "6.21.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-53946"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-04T21:25:21Z",
    "nvd_published_at": "2026-06-24T19:17:12Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nWhen re-rendering posts, Ghost would refetch missing image dimensions by issuing an outbound HTTP request to the URL stored on an image card \u2014 without restricting that URL to trusted image hosts. An authenticated staff user able to create or edit posts could therefore point an image card at an attacker-chosen host and cause the Ghost server to request it on their behalf, including hosts on internal networks or cloud instance metadata endpoints that would not normally be reachable from the public internet.\n\n### Vulnerable versions\n\nThis vulnerability is present in Ghost from v6.19.3 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### 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-g366-23fw-ggp6",
  "modified": "2026-08-04T21:25:21Z",
  "published": "2026-08-04T21:25:21Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/TryGhost/Ghost/security/advisories/GHSA-g366-23fw-ggp6"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53946"
    },
    {
      "type": "WEB",
      "url": "https://github.com/TryGhost/Ghost/pull/26753"
    },
    {
      "type": "WEB",
      "url": "https://github.com/TryGhost/Ghost/commit/ba692df7f27162d0440d57487f16c530416a8eb2"
    },
    {
      "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:L/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Ghost: Mobiledoc image-size fetch SSRF"
}



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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • 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.


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