SurrealDB: Custom API route lets authenticated callers override namespace/database scope via URL path (CVE-2026-63735)

The vulnerability (CVE-2026-63735) in SurrealDB affects the custom API route `/api/{namespace}/{database}/{endpoint}` where the namespace and database from the URL are applied to the caller's session without verifying that the caller is authorized for that scope. Because custom API handlers run with permissions disabled (definer's rights), the endpoint's own permissions clause is the only access control, which can be bypassed if set to 'PERMISSIONS FULL'. An attacker with valid credentials for any namespace/database can invoke APIs in other namespaces/databases, potentially reading or writing data across tenant boundaries. The issue is fixed in SurrealDB 3.2.0 by enforcing validation of the requested namespace/database against the caller's authenticated scope, returning 403 Forbidden if unauthorized.

An attacker with valid credentials scoped to any namespace/database can invoke custom APIs in other namespaces/databases, potentially accessing or modifying data they should not have access to. This includes reading data from tables with 'PERMISSIONS NONE' since the handler runs with permissions disabled, and triggering writes or side effects. The vulnerability does not allow unauthenticated access or affect single-tenant deployments or deployments where callers have instance-wide root scope.

A patch is available in SurrealDB version 3.2.0 and later that enforces validation of namespace/database scope against the caller's authenticated permissions, rejecting unauthorized cross-tenant API calls with a 403 Forbidden response. Users unable to upgrade should disable the custom API HTTP route where not required, treat separate deployments as tenant isolation boundaries instead of namespaces/databases, and prefer 'PERMISSIONS WHERE' clauses that check authenticated identity rather than 'PERMISSIONS FULL' to reduce exposure.