CVE-2026-27886 PoC — Strapi may leak sensitive data via relational filtering due to lack of query sanitization

https://github.com/projectdiscovery/nuclei-templates/blob/main/javascript/cves/2026/CVE-2026-27886.yaml

Title: Strapi may leak sensitive data via relational filtering due to lack of query sanitization (CVE-2026-27886)
Description:Strapi is an open source headless content management system. Strapi versions starting in 4.0.0 and prior to 5.37.0 did not sufficiently sanitize query parameters when filtering content via relational fields. An unauthenticated attacker could use the `where` query parameter on any publicly-accessible content-type with an `updatedBy` (or other admin-relation) field to perform a boolean-oracle attack against private fields on the joined `admin_users` table, including the `resetPasswordToken` field. Extracting an admin reset token via this oracle made full administrative account takeover possible without authentication. When a filter such as `where[updatedBy][resetPasswordToken][$startsWith]=a` was applied to a public Content API endpoint, the underlying query generation performed a `LEFT JOIN` against the `admin_users` table and emitted a `WHERE` clause referencing the joined column. The query parameter sanitization layer did not block operator chains that traversed into relational target schemas the caller had no read permission on, allowing the response count to be used as a one-bit oracle on any admin-table field. The patch in version 5.37.0 introduces explicit query-parameter sanitization at the controller and service boundary via three new primitives: `strictParam`, `addQueryParams`, and `addBodyParams`. Operator chains that traverse into restricted relational targets are now rejected before reaching the database.