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CVE-2026-39857

MEDIUM CVSS 3.1: 5.3
Updated Apr 17, 2026
MongoDB
Parameter Value
CVSS 5.3 (MEDIUM)
Fixed In 4.29.0
Type CWE-200 (Information Exposure)
Vendor MongoDB
Public PoC No

ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain an authorization bypass vulnerability in the choices and counts query parameters of the REST API, where these query builders execute MongoDB distinct() operations that bypass the publicApiProjection restrictions intended to limit which fields are exposed publicly. The choices and counts parameters are processed via applyBuildersSafely before the projection is applied, and MongoDB's distinct operation does not respect projections, returning all distinct values directly.

The results are returned in the API response without any filtering against publicApiProjection or removeForbiddenFields. An unauthenticated attacker can extract all distinct field values for any schema field type that has a registered query builder, including string, integer, float, select, boolean, date, slug, and relationship fields. Fields protected with viewPermission are similarly exposed, and the counts variant additionally reveals how many documents have each distinct value.

Both the piece-type and page REST APIs are affected. This issue has been fixed in version 4.29.0.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
Low
Partial data leak
Integrity
None
No data modification
Availability
None
No disruption

CVSS Vector v3.1

Weakness Type (CWE)