apostrophecms apostrophe up to 4.30.0 REST API Endpoint apos.util.set pullAll prototype pollution

Summaryinfo

A vulnerability classified as critical was found in apostrophecms apostrophe up to 4.30.0. This affects the function apos.util.set of the component REST API Endpoint. Such manipulation of the argument pullAll leads to prototype pollution. This vulnerability is referenced as CVE-2026-53609. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in apostrophecms apostrophe up to 4.30.0. It has been rated as critical. Affected by this issue is the function apos.util.set of the component REST API Endpoint. The manipulation of the argument pullAll with an unknown input leads to a prototype pollution vulnerability. Using CWE to declare the problem leads to CWE-1321. The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-53609 since 06/09/2026. The exploitation is known to be easy. The attack may be launched remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 06/13/2026). This vulnerability is assigned to T1059 by the MITRE ATT&CK project.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• apostrophecms

Name

• apostrophe

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9
• 4.10
• 4.11
• 4.12
• 4.13
• 4.14
• 4.15
• 4.16
• 4.17
• 4.18
• 4.19
• 4.20
• 4.21
• 4.22
• 4.23
• 4.24
• 4.25
• 4.26
• 4.27
• 4.28
• 4.29
• 4.30.0

Website

• Product: https://github.com/apostrophecms/apostrophe/

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