Vulnerability-Lookup

GHSA-944X-PM95-3JPR

Vulnerability from github – Published: 2026-08-04 21:05 – Updated: 2026-08-04 21:05

Summary

Ghost: File Upload Content-Type Spoofing

Details

Impact

Insufficient validation of the client-supplied Content-Type on Ghost's Admin API file upload endpoint allowed uploaded files to be served from the site with an attacker-chosen content type on S3/GCS storage backends. On installations that serve uploaded files from the same origin as the site, this could have been used to facilitate stored cross-site scripting against site visitors or staff.

Vulnerable versions

This vulnerability is present in Ghost from v6.19.4 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

JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "ghost"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.19.4"
            },
            {
              "fixed": "6.21.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-53948"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-434"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-04T21:05:39Z",
    "nvd_published_at": "2026-06-24T19:17:12Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nInsufficient validation of the client-supplied `Content-Type` on Ghost\u0027s Admin API file upload endpoint allowed uploaded files to be served from the site with an attacker-chosen content type on S3/GCS storage backends. On installations that serve uploaded files from the same origin as the site, this could have been used to facilitate stored cross-site scripting against site visitors or staff.\n\n### Vulnerable versions\n\nThis vulnerability is present in Ghost from v6.19.4 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-944x-pm95-3jpr",
  "modified": "2026-08-04T21:05:40Z",
  "published": "2026-08-04T21:05:39Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/TryGhost/Ghost/security/advisories/GHSA-944x-pm95-3jpr"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53948"
    },
    {
      "type": "WEB",
      "url": "https://github.com/TryGhost/Ghost/pull/26751"
    },
    {
      "type": "WEB",
      "url": "https://github.com/TryGhost/Ghost/commit/d659e752d6636144d75b9aa94062cdbc88a16b21"
    },
    {
      "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: File Upload Content-Type Spoofing"
}

CVE-2026-53948 (GCVE-0-2026-53948)

Vulnerability from cvelistv5 – Published: 2026-06-24 18:06 – Updated: 2026-06-25 13:17

Title

Ghost: File Upload Content-Type Spoofing

Summary

Ghost is a Node.js content management system. From 6.19.4 until 6.21.1, insufficient validation of the client-supplied Content-Type on Ghost's Admin API file upload endpoint allowed uploaded files to be served from the site with an attacker-chosen content type on S3/GCS storage backends. On installations that serve uploaded files from the same origin as the site, this could have been used to facilitate stored cross-site scripting against site visitors or staff. This vulnerability is fixed in 6.21.1.

Severity

5.4 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-25 13:17 UTC

CWE

CWE-434 - Unrestricted Upload of File with Dangerous Type

Assigner

GitHub_M mitre root Scorecard

References

1 reference

URL	Tags
https://github.com/TryGhost/Ghost/security/adviso…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
TryGhost	Ghost	Affected: >= 6.19.4, < 6.21.1

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-53948",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-25T13:17:17.045202Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-25T13:17:23.333Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Ghost",
          "vendor": "TryGhost",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 6.19.4, \u003c 6.21.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Ghost is a Node.js content management system. From 6.19.4 until 6.21.1, insufficient validation of the client-supplied Content-Type on Ghost\u0027s Admin API file upload endpoint allowed uploaded files to be served from the site with an attacker-chosen content type on S3/GCS storage backends. On installations that serve uploaded files from the same origin as the site, this could have been used to facilitate stored cross-site scripting against site visitors or staff. This vulnerability is fixed in 6.21.1."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.4,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-434",
              "description": "CWE-434: Unrestricted Upload of File with Dangerous Type",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-24T18:06:30.077Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/TryGhost/Ghost/security/advisories/GHSA-944x-pm95-3jpr",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/TryGhost/Ghost/security/advisories/GHSA-944x-pm95-3jpr"
        }
      ],
      "source": {
        "advisory": "GHSA-944x-pm95-3jpr",
        "discovery": "UNKNOWN"
      },
      "title": "Ghost: File Upload Content-Type Spoofing"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-53948",
    "datePublished": "2026-06-24T18:06:30.077Z",
    "dateReserved": "2026-06-11T15:50:01.281Z",
    "dateUpdated": "2026-06-25T13:17:23.333Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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