dbcve.org
Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-53950

HIGH · 7.5 CVSS v3.1 Published 2026-06-24
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
82/100
Remediation priority · High
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
@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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The @tryghost/activitypub package versions prior to 3.1.0 are vulnerable to JavaScript injection. The ActivityPub client fails to properly sanitize or validate content received from ActivityPub servers, allowing a maliciously customized server to inject and execute arbitrary JavaScript code in posts shared to the Ghost instance.

MitigationUpgrade @tryghost/activitypub to version 3.1.0 or later to remediate this vulnerability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify @tryghost/activitypub package version
    Run 'npm list @tryghost/activitypub' or check the package.json dependencies in your Ghost installation directory
    Affected if The installed version is lower than 3.1.0 or the package is not listed in your dependencies but ActivityPub functionality exists
  2. Confirm ActivityPub module is enabled
    Check your Ghost config file (config.production.json or config.development.json) for the 'activitypub' key under 'labs' or 'api' settings, or inspect the active plugins/modules
    Affected if ActivityPub integration is explicitly enabled in the configuration
  3. Verify ActivityPub incoming content handling
    Review your Ghost activity logs or database records for entries in tables related to ActivityPub inbox processing (e.g., any table storing inbound ActivityPub notes or posts)
    Affected if The instance processes or stores incoming ActivityPub content from external servers
  4. Check for external ActivityPub server connections
    Inspect the database or configuration for ActivityPub actor/remote profiles that your Ghost instance follows or has federated with
    Affected if The Ghost instance has established federated connections to external ActivityPub servers or accepts inbound posts from them

You are affected if @tryghost/activitypub version is below 3.1.0 AND the ActivityPub feature is enabled with potential exposure to external ActivityPub servers sending content

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade @tryghost/activitypub to version 3.1.0 or later to remediate this vulnerability.

Recommended fix High confidence

@tryghost/activitypub version 3.1.0

  1. Identify the current version of @tryghost/activitypub in your Ghost installation by checking package.json or lock file
  2. Run 'npm install @tryghost/[email protected]' to upgrade to the fixed version
  3. Verify the upgrade was successful by confirming the installed version matches 3.1.0
  4. Test ActivityPub functionality to ensure the upgrade does not break existing features
  5. Deploy the updated package to your production environment
Caveat Review the Ghost 3.1.0 release notes for any breaking changes in the ActivityPub module before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-53950 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data