surrealdb: Cross-tenant access through the USE statement

An authenticated user scoped to one namespace/database could read, modify, and delete data in another namespace/database on the same instance by switching to it with the SurrealQL USE statement.

USE NS … DB … moved the session to any requested namespace/database without checking that the caller's authenticated level covered it. After the switch, the caller's identity stayed bound to their own tenant, but queries ran against the foreign one, where the only remaining gate was the table's PERMISSIONS clause. So a table declared PERMISSIONS FULL, or with a predicate the caller happened to satisfy, admitted the request. That is a common table shape when the namespace/database itself is treated as the tenant boundary.

For example, a database user of ns_a/db_a could run:

USE NS ns_b DB db_b;
SELECT * FROM secrets;             -- read another tenant's rows
UPDATE secrets:1 SET owned = true; -- modify them
DELETE secrets:2;                  -- delete them

This is the same control that was fixed for the custom API route in GHSA-848m-r628-vrxw. That fix did not extend to the USE statement.

The same root cause was reported through several paths, each published as its own advisory and all fixed in 3.3.0:

• GHSA-vx2p-7hhm-wv62: the Surreal-NS / Surreal-DB headers with Basic authentication
• GHSA-w5v9-jc5f-5rmc: the headers and the RPC use method, for system users
• GHSA-3vw5-j55x-486h: RETURN … FETCH, for record users

Impact

What an attacker can do:

• With a database- or namespace-level account in any one tenant, switch to another tenant with USE. They can then read, create, update, and delete rows in its tables whose PERMISSIONS allow the operation, such as PERMISSIONS FULL.
• As a record user, write to another tenant's tables whose PERMISSIONS allow it, even though record users' direct table scans in a foreign tenant were denied.

What it can't do:

• Reach any tenant without valid credentials for some namespace/database on the instance. This is not an unauthenticated bypass.
• Read or write a table whose relevant PERMISSIONS clause denies the operation, including PERMISSIONS NONE (the DEFINE TABLE default).
• Pass IAM-gated operations such as INFO FOR DB, or change roles.
• Affect single-tenant deployments, or callers that already hold instance-wide (root) scope.

Patches

A request can no longer select a namespace/database outside the caller's authenticated level. The check applies to the USE statement, the RPC use method, and HTTP sessions built from the Surreal-NS / Surreal-DB headers. Root can select any namespace/database, and a namespace user any database in their namespace. Database and record users can select only their own namespace/database. Anonymous callers remain governed by table PERMISSIONS.

The query-time scope checks now apply to every scoped principal, not only record users. They also cover record fetches and the document write pipeline, so a read or write in a foreign tenant is refused however the session reached it.

• Versions 3.3.0 and later are not affected by this issue.

Workarounds

Users unable to patch should consider the following workarounds:

• On shared instances, use separate deployments, not namespace/database boundaries, to isolate tenants. Until you upgrade, issue namespace-, database-, and record-level credentials only to parties trusted with every tenant on the instance.
• Prefer a PERMISSIONS WHERE clause that checks the caller's identity, such as $auth or a token claim, over PERMISSIONS FULL. This reduces exposure but does not restore the boundary.

References

• SurrealQL Documentation — USE
• SurrealQL Documentation — DEFINE TABLE … PERMISSIONS
• SurrealDB Documentation — Security and authentication
• fix(core): enforce tenant boundary on USE / process_use (included in SurrealDB 3.3.0)
• fix(server): confine Surreal-NS/Surreal-DB header context to the auth level (included in SurrealDB 3.3.0)
• fix(core): confine record users to their own tenant on the write path (included in SurrealDB 3.3.0)
• fix(doc): re-verify record-auth namespace/database scope in the document pipeline (included in SurrealDB 3.3.0)

Acknowledgements

Thank you to xaxaks for reporting this issue.