Information Disclosure via `choices`/`counts` Query Parameters Bypassing publicApiProjection Field Restrictions

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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.

Source published

15 Apr 2026 19:38:57 UTC

Source modified

16 Apr 2026 13:40:17 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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.

Source published

Apr 15, 2026, 7:38:57 PM (timezone not stated)

Source modified

Apr 16, 2026, 1:40:17 PM (timezone not stated)

Observed here

1 Nov 2026 06:14:25 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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.

Source published

15 Apr 2026 20:16:36 UTC

Source modified

26 Oct 2026 22:10:00 UTC

Observed here

27 Oct 2026 10:09:56 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

## Summary The `choices` and `counts` query parameters in the Apostrophe CMS REST API allow unauthenticated users to extract distinct field values for any schema field that has a registered query builder, completely bypassing `publicApiProjection` restrictions that are intended to limit which fields are exposed publicly. Fields protected by `viewPermission` are similarly exposed. ## Details When a piece type configures `publicApiProjection` to enable public API access while restricting visible fields, the restriction is enforced via a MongoDB projection on the main query (piece-type/index.js:1130-1134). However, the `choices` and `counts` query builders bypass this protection through a separate code path. The vulnerable flow: 1. `getRestQuery` at piece-type/index.js:1120 calls `applyBuildersSafely(req.query)` (line 1122), which processes query parameters including `choices` and `counts` since both have `launder` methods (doc-type/index.js:2627-2628 and 2675-2676). 2. The `publicApiProjection` is applied afterward (line 1130-1134) as a MongoDB projection on the main query. 3. During query execution, the `choices` builder's `after` handler (doc-type/index.js:2636-2668) iterates over requested field names. The only validation is: - The field has a registered builder (`_.has(query.builders, filter)` at line 2651) - The builder has a `launder` method (line 2656) All schema field types (string, integer, float, select, boolean, date, slug, relationship) register query builders with `launder` methods via `addQueryBuilder` in `addFieldTypes.js`. 4. `toChoices` (line 2661) calls the field's `choices` function, which typically calls `sortedDistinct` → `toDistinct`. The `toDistinct` method (doc-type/index.js:2811) executes `db.distinct(property, criteria)` — a MongoDB operation that returns all distinct values for the given property matching the criteria. **MongoDB's `distinct` operation does not respect projections**; it operates directly on the specified field regardless of any projection set on the query. 5. The results are stored via `query.set('choicesResults', choices)` (line 2666) and returned directly in the API response at piece-type/index.js:292-296 without any filtering against `publicApiProjection` or `removeForbiddenFields`. The same bypass applies to `viewPermission`-protected fields: `removeForbiddenFields` (doc-type/index.js:1585-1611) only processes document results from `toArray()`, not the separate choices/counts data. The page REST API has the same issue at page/index.js:371-376. ## PoC ```bash # Prerequisites: # - An Apostrophe 4.x instance with a piece type configured with publicApiProjection # - Example: an 'article' piece type with: # publicApiProjection: { title: 1, slug: 1, _url: 1 } # and additional schema fields like 'status' (select), 'priority' (integer), # or 'internalNotes' (string) NOT in the projection # 1. Verify normal API access only returns projected fields curl -s 'http://localhost:3000/api/v1/article' | python3 -m json.tool # Response results contain only: title, slug, _url (as configured) # 2. Extract distinct values of a non-projected field via choices curl -s 'http://localhost:3000/api/v1/article?choices=status' | python3 -m json.tool # Response includes: # "choices": {"status": [{"value": "draft", "label": "draft"}, {"value": "published", "label": "published"}, ...]} # 3. Extract distinct values with document counts via counts curl -s 'http://localhost:3000/api/v1/article?counts=priority' | python3 -m json.tool # Response includes: # "counts": {"priority": [{"value": 1, "label": "1", "count": 15}, {"value": 2, "label": "2", "count": 8}, ...]} # 4. Multiple fields can be extracted at once curl -s 'http://localhost:3000/api/v1/article?choices=status,priority,internalNotes' ``` ## Impact - **Distinct field values leaked**: An unauthenticated attacker can extract all distinct values of any schema field on any piece type that has `publicApiProjection` configured, even when those fields are explicitly excluded from the projection. - **Field types affected**: All field types that register query builders: string, slug, integer, float, select, boolean, date, and relationship fields. - **Count disclosure**: The `counts` variant additionally reveals how many documents have each distinct value, providing statistical information about the dataset. - **viewPermission bypass**: Fields protected with `viewPermission` (intended for role-based field access) are also exposed via this path. - **Both APIs affected**: The piece-type REST API (piece-type/index.js:292-296) and page REST API (page/index.js:371-376) are both vulnerable. - **Real-world impact**: If a CMS stores sensitive data in schema fields (e.g., internal status values, priority levels, internal categories, user-facing content marked as restricted), all distinct values are extractable by any unauthenticated visitor. ## Recommended Fix In the `choices` builder's `after` handler (doc-type/index.js:2636-2668), add validation to skip fields not permitted by `publicApiProjection` and `viewPermission`: ```javascript // doc-type/index.js, in the choices builder's after handler (line 2644 area) for (const filter of filters) { if (!_.has(query.builders, filter)) { continue; } if (!query.builders[filter].launder) { continue; } // NEW: Enforce publicApiProjection restrictions on choices/counts const publicApiProjection = query.get('project'); if (publicApiProjection && !publicApiProjection[filter]) { continue; } // NEW: Enforce viewPermission field restrictions const field = self.schema.find(f => f.name === filter); if (field && field.viewPermission && !self.apos.permission.can(query.req, field.viewPermission.action, field.viewPermission.type)) { continue; } const _query = baseQuery.clone(); _query[filter](null); choices[filter] = await _query.toChoices(filter, { counts: query.get('counts') }); } ``` Additionally, apply the same fix in the page REST API handler (page/index.js) for consistency.

Source published

16 Apr 2026 20:45:15 UTC

Source modified

16 Apr 2026 21:11:29 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Publisher rating · MODERATE