CVE-2026-53609 — CRITICAL (9.1)

Vulnerability Description

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.

CVSS Score

9.1

CRITICAL

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

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality

HIGH

Integrity

LOW

Availability

LOW

Related Weaknesses (CWE)

CWE-1321

References

FAQ

What is CVE-2026-53609?

CVE-2026-53609 is a vulnerability with a CVSS score of 9.1 (CRITICAL). 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 au...

How severe is CVE-2026-53609?

CVE-2026-53609 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2026-53609?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.