CVE-2026-30241 Mercurius: queryDepth limit bypassed for WebSocket subscriptions

Mercurius is a GraphQL adapter for Fastify. Prior to version 16.8.0, Mercurius fails to enforce the configured queryDepth limit on GraphQL subscription queries received over WebSocket connections. The depth check is correctly applied to HTTP queries and mutations, but subscription queries are...

Uncontrolled Recursion

Overview mercurius is a GraphQL adapter for Fastify Affected versions of this package are vulnerable to Uncontrolled Recursion in the subscription queries received over WebSocket connections. An attacker can bypass intended query depth restrictions by submitting deeply nested subscription queries...

Mercurius's queryDepth limit bypassed for WebSocket subscriptions

Description Mercurius fails to enforce the configured queryDepth limit on GraphQL subscription queries received over WebSocket connections. The depth check is correctly applied to HTTP queries and mutations, but subscription queries are parsed and executed without invoking the depth validation...