The HTTP /rpc sessions method returned every attached session UUID without authentication, and the /rpc handler accepted an arbitrary session field with no ownership check. An anonymous caller could enumerate UUIDs and impersonate any authenticated session.
"Attached" means sessions registered via {"method":"attach"} — the only writer to the HTTP session map. Ordinary stateless /rpc requests use ephemeral per-request sessions that are filtered from sessions() and destroyed at end-of-request, so they are not enumerable.
Exposure
- Exposed: clients that issue
attach, notably the official Rust SDK's Http/Https engine (auto-attaches once per Surreal handle).
- Not exposed: REST endpoints (
/sql, /key, /signin, /export, etc.); WebSocket /rpc (per-connection scope, attach refused); embedded / MCP usage; ad-hoc POST /rpc callers that never attach.
Impact
For each attached and authenticated session, an unauthenticated attacker can read, write, and delete any data the session can reach, dump metadata, invalidate sessions, and escalate to that session's privilege level (up to root). An attached session that has not yet authenticated is Level::No and confers no privilege.
Patches
- HTTP
sessions() now returns method_not_allowed. WebSocket retains per-connection enumeration.
- The HTTP
/rpc handler gates client-supplied session IDs against the caller's request-level auth principal (actor id + level); mismatches return session_not_found.
- Attached HTTP sessions are capped via
SURREAL_HTTP_MAX_ATTACHED_SESSIONS.
Versions 3.1.0 and later are not affected.
Workarounds
No configuration-level mitigation fully addresses this. For Users unable to upgrade:
- Avoid SDKs and client flows that call
attach against HTTP /rpc (notably the Rust SDK's Http/Https engine). Prefer the WebSocket transport, or REST endpoints (/sql, /signin, /key, /export) which never populate the attached-session map.
- Restrict
/rpc to trusted clients at the network layer.
References
addcontent Reporter
The HTTP
/rpcsessionsmethod returned every attached session UUID without authentication, and the/rpchandler accepted an arbitrarysessionfield with no ownership check. An anonymous caller could enumerate UUIDs and impersonate any authenticated session."Attached" means sessions registered via
{"method":"attach"}— the only writer to the HTTP session map. Ordinary stateless/rpcrequests use ephemeral per-request sessions that are filtered fromsessions()and destroyed at end-of-request, so they are not enumerable.Exposure
attach, notably the official Rust SDK'sHttp/Httpsengine (auto-attaches once perSurrealhandle)./sql,/key,/signin,/export, etc.); WebSocket/rpc(per-connection scope,attachrefused); embedded / MCP usage; ad-hocPOST /rpccallers that neverattach.Impact
For each attached and authenticated session, an unauthenticated attacker can read, write, and delete any data the session can reach, dump metadata, invalidate sessions, and escalate to that session's privilege level (up to root). An attached session that has not yet authenticated is
Level::Noand confers no privilege.Patches
sessions()now returnsmethod_not_allowed. WebSocket retains per-connection enumeration./rpchandler gates client-supplied session IDs against the caller's request-level auth principal (actor id + level); mismatches returnsession_not_found.SURREAL_HTTP_MAX_ATTACHED_SESSIONS.Versions 3.1.0 and later are not affected.
Workarounds
No configuration-level mitigation fully addresses this. For Users unable to upgrade:
attachagainst HTTP/rpc(notably the Rust SDK'sHttp/Httpsengine). Prefer the WebSocket transport, or REST endpoints (/sql,/signin,/key,/export) which never populate the attached-session map./rpcto trusted clients at the network layer.References