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CWE-1321Weakness · CWE-1321

CVE-2026-53609

CRITICAL · 9.1 CVSS v3.1 Published 2026-06-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
97/100
Remediation priority · Urgent
Remotely reachable Zero-click

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
ApostropheCMS is an open-source Node.js content management system. In versions up to and including 4.30.0, `apos.util.set()` traverses dot-notation paths without sanitizing `__proto__`, allowing an authenticated editor to write arbitrary values to `Object.prototype` via the `$pullAll` patch operator. A confirmed gadget in `publicApiCheck()` causes this to bypass authorization on all piece-type REST API endpoints for every subsequent unauthenticated request, for the lifetime of the Node.js process. As of time of publication, no known patched versions are available.

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

ApostropheCMS versions up to 4.30.0 contain a prototype pollution vulnerability in apos.util.set() which fails to sanitize __proto__ in dot-notation paths. When combined with the $pullAll patch operator, an authenticated editor can inject arbitrary properties into Object.prototype, triggering a confirmed gadget in publicApiCheck() that permanently bypasses authentication for all piece-type REST API endpoints.

MitigationSince no patch is available, implement input validation to reject __proto__ and $pullAll in patch requests, or restrict editor-role permissions until an official patch is released. Consider disabling REST API endpoints or adding WAF rules blocking __proto__ in request bodies.

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
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
Low

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

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 installed ApostropheCMS version
    Check your package.json file for the apostrophe version, or run 'npm list apostrophe' in your project directory
    Affected if The version is 4.x and is less than or equal to 4.30.0 (or if you cannot confirm the exact version and are on 4.x)
  2. Verify editor-level accounts exist
    Query your users database collection for documents where the type is 'editor' or review your user role assignments in the Apostrophe admin panel
    Affected if There is at least one user account with editor-level permissions who could authenticate to the CMS
  3. Confirm REST API piece endpoints are exposed
    Check your app configuration for pieces REST API routes (typically at /api/v1/<piece-name>) and verify they accept PATCH requests
    Affected if Piece-type REST API endpoints are publicly accessible or accessible to editor-level accounts and accept PATCH operations
  4. Inspect $pullAll operator handling in API code
    Review your ApostropheCMS project for custom API handlers or middleware that process PATCH requests with the $pullAll operator in the query or body
    Affected if $pullAll is accepted in patch operations without explicit validation blocking __proto__ or Object.prototype manipulation

You are likely affected if running ApostropheCMS 4.30.0 or lower with exposed piece-type REST API endpoints and editor-level accounts able to make authenticated PATCH requests.

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

Since no patch is available, implement input validation to reject __proto__ and $pullAll in patch requests, or restrict editor-role permissions until an official patch is released. Consider disabling REST API endpoints or adding WAF rules blocking __proto__ in request bodies.

Recommended fix High confidence
  1. No remediation steps available. The vendor has confirmed that no patched version exists as of the time of this vulnerability's publication.
  2. Monitor the official ApostropheCMS GitHub repository and security advisories for future security releases.
  3. Consider implementing additional authentication layers (such as API gateways with stricter controls) as a temporary compensating control until a patch is released.

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

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2026-53609 in production — separate from our analysis above.

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What this is

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  • Version or environment caveats, and links to real fixes
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