CVE-2026-33326: @keystone-6/core: `isFilterable` bypass via `cursor` parameter in findMany

Summary {field}.isFilterable access control can be bypassed in findMany queries by passing a cursor. This can be used to confirm the existence of records by protected field values.

The fix for CVE-2025-46720 (field-level isFilterable bypass for update and delete mutations) added checks to the where parameter in update and delete mutations however the cursor parameter in findMany was not patched and accepts the same UniqueWhere input type.

Impact This affects any project relying on isFilterable behaviour (at the list or field level) to prevent external users from using the filtering of fields as a discovery mechanism. isFilterable access control using a function can be bypassed by using the cursor input.

This has no impact on projects using isFilterable: false or defaultIsFilterable: false for sensitive fields, or if you have otherwise omitted filtering by these fields from your GraphQL schema. (See workarounds)

Patches This issue has been patched in @keystone-6/core version 6.5.2.

Workarounds To mitigate this issue in older versions where patching is not a viable pathway.

- Set {field}.isFilterable: false statically for relevant fields to prevent filtering by them earlier in the access control pipeline (that is, don't use functions) - Set {field}.graphql.omit.read: true for relevant fields, which implicitly removes filtering by these fields your GraphQL schema