Vulnerability-Lookup

GHSA-XPP7-93X6-V29M

Vulnerability from github – Published: 2026-08-04 21:54 – Updated: 2026-08-04 21:54

Summary

XSS in Ghost's ActivityPub client

Details

Impact

The ActivityPub client in Ghost was vulnerable to JavaScript injection on posts shared by a maliciously customised ActivityPub server.

Vulnerable Versions

This vulnerability is present in the @tryghost/activitypub package up to v3.0.8. All prior versions are also affected.

Patches

@tryghost/activitypub v3.1.0 contains a fix for this issue and is also automatically fetched by Ghost.

References

Ghost thanks Brad Geesaman, Ghost Security for disclosing this vulnerability responsibly.

For more information

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

Severity

7.5 (High)


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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "@tryghost/activitypub"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-53950"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-04T21:54:01Z",
    "nvd_published_at": "2026-06-24T19:17:12Z",
    "severity": "HIGH"
  },
  "details": "### Impact\n\nThe ActivityPub client in Ghost was vulnerable to JavaScript injection on posts shared by a maliciously customised ActivityPub server.\n\n### Vulnerable Versions\n\nThis vulnerability is present in the @tryghost/activitypub package up to v3.0.8. All prior versions are also affected. \n\n### Patches\n\n@tryghost/activitypub v3.1.0 contains a fix for this issue and is also automatically fetched by Ghost.\n\n### References\n\nGhost thanks Brad Geesaman, Ghost Security for disclosing this vulnerability responsibly. \n\n### For more information\n\nIf you have any questions or comments about this advisory, email Ghost at [security@ghost.org](mailto:security@ghost.org).",
  "id": "GHSA-xpp7-93x6-v29m",
  "modified": "2026-08-04T21:54:01Z",
  "published": "2026-08-04T21:54:01Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/TryGhost/Ghost/security/advisories/GHSA-xpp7-93x6-v29m"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53950"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/TryGhost/Ghost"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "XSS in Ghost\u0027s ActivityPub client"
}

CVE-2026-53950 (GCVE-0-2026-53950)

Vulnerability from cvelistv5 – Published: 2026-06-24 18:04 – Updated: 2026-06-24 18:49

Title

@tryghost/activitypub: XSS in Ghost's ActivityPub client

Summary

@tryghost/activitypub is Ghost’s social/federation client app. Prior to 3.1.0, the ActivityPub client in Ghost was vulnerable to JavaScript injection on posts shared by a maliciously customised ActivityPub server. This vulnerability is fixed in 3.1.0.

Severity

7.5 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-24 18:49 UTC

CWE

CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7712 records in the last 180 days details

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: < 3.1.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-53950",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-24T18:49:49.390982Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-24T18:49:55.010Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Ghost",
          "vendor": "TryGhost",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 3.1.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "@tryghost/activitypub is Ghost\u2019s social/federation client app. Prior to 3.1.0, the ActivityPub client in Ghost was vulnerable to JavaScript injection on posts shared by a maliciously customised ActivityPub server. This vulnerability is fixed in 3.1.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-79",
              "description": "CWE-79: Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-24T18:04:25.695Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/TryGhost/Ghost/security/advisories/GHSA-xpp7-93x6-v29m",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/TryGhost/Ghost/security/advisories/GHSA-xpp7-93x6-v29m"
        }
      ],
      "source": {
        "advisory": "GHSA-xpp7-93x6-v29m",
        "discovery": "UNKNOWN"
      },
      "title": "@tryghost/activitypub: XSS in Ghost\u0027s ActivityPub client"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-53950",
    "datePublished": "2026-06-24T18:04:25.695Z",
    "dateReserved": "2026-06-11T15:50:01.281Z",
    "dateUpdated": "2026-06-24T18:49:55.010Z",
    "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.

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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.
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GHSA-XPP7-93X6-V29M

Impact

Vulnerable Versions

Patches

References

For more information

CVE-2026-53950 (GCVE-0-2026-53950)

Tags

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Nomenclature

Vulnerability timeline

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