SurrealDB: Graph traversal bypasses table SELECT permissions

An authenticated record or scope user could read records on any table reachable through a graph edge or REFERENCES TO back-reference, regardless of that table's PERMISSIONS FOR select clause.

Traversing SELECT * FROM source->edge->target returned full documents from target even when target was defined as PERMISSIONS FOR select NONE. The same bypass extended through multi-hop chains, so any table reachable by a sequence of edges from a readable starting point was exposed.

The root cause: GraphEdgeScan and ReferenceScan fetched records straight from storage without routing them through Document::pluck_select, so the target table's permission expression was never consulted.

Impact

An authenticated record or scope user can read records on any table reachable through a chain of graph edges or back-references from a table they have select on, regardless of the target's PERMISSIONS FOR select clause. Confidentiality-only and bounded to the caller's current database — namespace and database isolation are unaffected.

Patches

A new per-batch permission cache (exec::permission::CachedTableSelect) resolves each target table's SELECT permission once and filters yielded values through check_permission_for_value, matching the regular SELECT code path.

• Versions 3.1.0 and later are not affected.

Workarounds

• Remove select permission on edge tables whose targets should be hidden.
• Use namespace or database isolation as the primary boundary where feasible.