GHSA-c8jx-96c9-8xrp: SurrealDB: Field-level SELECT permissions bypassed via indexed COUNT fast paths

A record user could learn the value of a hidden field by counting how many records match a guess.

When DEFINE FIELD ... PERMISSIONS FOR select WHERE ... hides a field’s contents from a caller, and that field is indexed, running SELECT count() FROM t WHERE hidden_field = "guess" GROUP ALL returned a count greater than zero whenever a record actually had that value — even though the caller was never allowed to read the field directly. The query planner used an indexed-COUNT shortcut (Index::Count, IndexCountScan, or the legacy Iterate Index Count / Iterate Index Keys paths) that counts matching index entries and skips the permission check that would normally hide the value. The same query with WITH NOINDEX correctly returned [], confirming the gap.

By repeating the count query with different guesses, an attacker can confirm or recover the contents of any restricted field they could not read through a normal SELECT.