Medium severity · published Apr 15, 2026
CVE-2026-39857
Information Disclosure via `choices`/`counts` Query Parameters Bypassing publicApiProjection Field Restrictions
5.3
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AP
apostrophe · apostrophecms
< 4.29.0 · source: vendor
AP
Apostrophecms · Apostrophecms
before 4.29.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-39857
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-39857
Patch
https://github.com/apostrophecms/apostrophe/commit/6c2b548dec2e3f7a82e8e16736603f4cd17525aa
Exploit
https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-c276-fj82-f2pq
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