Vulnerability-Lookup

GHSA-62Q6-4HV4-VJRW

Vulnerability from github – Published: 2026-07-01 21:58 – Updated: 2026-07-01 21:58

Summary

Ghost: Cache-poisoning XSS in Ghost frontend via x-ghost-preview header

Details

Impact

When Ghost is behind a shared caching layer that results in cached content being shared between different visitors (e.g., Fastly, Cloudflare, nginx proxy_cache, and others), an unauthenticated user could send an x-ghost-preview header that altered the rendered frontend response. In affected cache configurations, that response could be stored and served to subsequent visitors requesting the same page, allowing cache poisoning of request-specific preview output.

When running Ghost's frontend and admin panel on the same domain this could be used to take over staff user accounts. When running these on different domains staff accounts have no exposure.

Vulnerable versions

This vulnerability is present in Ghost from v4.0 up to v6.36.0.

Patches

v6.37.0 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.

If you suspect a credential compromise, use the “Reset all authentication” dialogue under Settings / Danger Zone. This is available starting with Ghost v6.41.0.

Workarounds

At the caching layer, bypass the cache for x-ghost-preview requests.

References

Ghost thanks CryptoCat 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

9.6 (Critical)


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

Show details on source website

JSON

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 6.36.0"
      },
      "package": {
        "ecosystem": "npm",
        "name": "ghost"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.0.0"
            },
            {
              "fixed": "6.37.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-53943"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-524"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-01T21:58:32Z",
    "nvd_published_at": "2026-06-24T19:17:11Z",
    "severity": "CRITICAL"
  },
  "details": "### Impact\n\nWhen Ghost is behind a shared caching layer that results in cached content being shared between different visitors (e.g., Fastly, Cloudflare, nginx proxy_cache, and others), an unauthenticated user could send an `x-ghost-preview` header that altered the rendered frontend response. In affected cache configurations, that response could be stored and served to subsequent visitors requesting the same page, allowing cache poisoning of request-specific preview output. \n\nWhen running Ghost\u0027s frontend and admin panel on the same domain this could be used to take over staff user accounts. When running these on different domains staff accounts have no exposure. \n\n### Vulnerable versions\n\nThis vulnerability is present in Ghost from v4.0 up to v6.36.0.\n\n### Patches\n\nv6.37.0 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\nIf you suspect a credential compromise, use the \u201cReset all authentication\u201d dialogue under Settings / Danger Zone. This is available starting with Ghost v6.41.0. \n\n### Workarounds\n\nAt the caching layer, bypass the cache for `x-ghost-preview` requests. \n\n### References\n\nGhost thanks [CryptoCat](https://linkedin.com/in/cryptocat) 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-62q6-4hv4-vjrw",
  "modified": "2026-07-01T21:58:32Z",
  "published": "2026-07-01T21:58:32Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/TryGhost/Ghost/security/advisories/GHSA-62q6-4hv4-vjrw"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53943"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/TryGhost/Ghost"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Ghost: Cache-poisoning XSS in Ghost frontend via x-ghost-preview header"
}

CVE-2026-53943 (GCVE-0-2026-53943)

Vulnerability from cvelistv5 – Published: 2026-06-24 18:13 – Updated: 2026-06-24 18:48

Title

Ghost: Cache-poisoning XSS in Ghost frontend via x-ghost-preview header

Summary

Ghost is a Node.js content management system. From until 6.37.0, when Ghost is behind a shared caching layer that results in cached content being shared between different visitors, an unauthenticated user could send an x-ghost-preview header that altered the rendered frontend response. In affected cache configurations, that response could be stored and served to subsequent visitors requesting the same page, allowing cache poisoning of request-specific preview output. When running Ghost's frontend and admin panel on the same domain this could be used to take over staff user accounts. When running these on different domains staff accounts have no exposure. This vulnerability is fixed in 6.37.0.

Severity

9.6 (Critical)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator (v2.0.3)

CWE

CWE-524 - Use of Cache Containing Sensitive Information

Assigner

GitHub_M

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: >= 4.0.0, < 6.37.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-53943",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-24T18:40:56.579441Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-24T18:48:56.416Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Ghost",
          "vendor": "TryGhost",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 4.0.0, \u003c 6.37.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Ghost is a Node.js content management system. From  until 6.37.0, when Ghost is behind a shared caching layer that results in cached content being shared between different visitors, an unauthenticated user could send an x-ghost-preview header that altered the rendered frontend response. In affected cache configurations, that response could be stored and served to subsequent visitors requesting the same page, allowing cache poisoning of request-specific preview output. When running Ghost\u0027s frontend and admin panel on the same domain this could be used to take over staff user accounts. When running these on different domains staff accounts have no exposure. This vulnerability is fixed in 6.37.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 9.6,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-524",
              "description": "CWE-524: Use of Cache Containing Sensitive Information",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-24T18:13:04.114Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/TryGhost/Ghost/security/advisories/GHSA-62q6-4hv4-vjrw",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/TryGhost/Ghost/security/advisories/GHSA-62q6-4hv4-vjrw"
        }
      ],
      "source": {
        "advisory": "GHSA-62q6-4hv4-vjrw",
        "discovery": "UNKNOWN"
      },
      "title": "Ghost: Cache-poisoning XSS in Ghost frontend via x-ghost-preview header"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-53943",
    "datePublished": "2026-06-24T18:13:04.114Z",
    "dateReserved": "2026-06-11T15:50:01.280Z",
    "dateUpdated": "2026-06-24T18:48:56.416Z",
    "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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-62Q6-4HV4-VJRW

Impact

Vulnerable versions

Patches

How to update

Workarounds

References

For more information

CVE-2026-53943 (GCVE-0-2026-53943)

Tags

Sightings

Nomenclature