SurrealDB: Field-level SELECT permissions bypassed via indexed COUNT fast paths
Date: 2026-07
Affected: rust/surrealdb
Attack vector: auth-bypass
Category: vulnerability-disclosure
Severity: Medium
CWE: CWE-863
CVSS: 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N)

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`. ### Impact What an attacker **can** do: - Confirm or recover values of a field protected by field-level SELECT permissions on any table they hold table-level SELECT on, provided the field is indexed. - Repeat the query with different guesses to read restricted field contents one value at a time. What it **can't** do: - Read fields that are not indexed (the shortcut only fires when an index covers the predicate column). - Cross table, database or namespace isolation boundaries. - Modify data, escalate privileges, or affect availability. ### P


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