Apostrophe has Server-Side Prototype Pollution in apos.util.set via patch operators that leads to process-wide authorization bypass
CVE-2026-53609

9.1CRITICAL

Key Information:

Vendor

Apostrophecms

Status
Apostrophe
Vendor
CVE Published:
12 June 2026

What is CVE-2026-53609?

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.

Affected Version(s)

apostrophe <= 4.30.0

References

https://github.com/apostrophecms/apostrophe/security/advi...
x_refsource_CONFIRM

CVSS V3.1

Score:
9.1
Severity:
CRITICAL
Confidentiality:
High
Integrity:
Low
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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