The SurrealDB type/kind parser did not enforce the configured recursion depth limit when parsing nested type annotations. The expression parser already enforced the limit for analogous constructs; the kind parser omitted it. An authenticated attacker could send a query with deeply nested type annotations (e.g., array<option<array<option<...>>>>) and exhaust server memory, crashing the process.

This is an incomplete fix for GHSA-6r8p-hpg7-825g, which addressed the same class of bug in the expression parser but did not cover the kind/type annotation parser code path.

An authenticated user with query execution privileges can crash a SurrealDB server with a single WebSocket message containing deeply nested type annotations.

A patch has been introduced that wraps parse concrete kind and the OPTION<...> arm of parse inner kind with enter object recursion!, bounding the recursive cycle parse concrete kind → parse inner kind → parse inner single kind → parse concrete kind at the configured object recursion limit (default 100). Regression tests cover both cast and DEFINE FIELD paths.

Restrict the ability of untrusted users to execute arbitrary queries via the --deny-arbitrary-query capability flag for the affected user classes (guest, record, or system). Disabling untrusted access to the WebSocket /rpc endpoint also prevents exploitation; the HTTP /sql endpoint's 1 MiB body limit constrains nesting to a depth where OOM is not feasible.