GHSA-6q22-g298-grjh: Directus: Unauthenticated Denial of Service via GraphQL Alias Amplification of Expensive Health Check Resolver

The GraphQL specification permits a single query to repeat the same field multiple times using aliases, with each alias resolved independently by default. Directus did not deduplicate resolver invocations within a single request, meaning each alias triggered a full, independent execution of the underlying resolver.

The health check resolver ran all backend checks (database connectivity, cache, storage writes, and SMTP verification) on every invocation. Combined with unauthenticated access to the system GraphQL endpoint, this allowed an attacker to amplify resource consumption significantly from a single HTTP request, exhausting the database connection pool, storage I/O, and SMTP connections.