Vulnerability Advisory : Parse Server crash via deeply nested query condition operators with LOW Attack Complexity

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 9.6.0-alpha.21 and 8.6.45, an unauthenticated attacker can crash the Parse Server process by sending a single request with deeply nested query condition operators. This terminates the server and denies service to all connected clients. Starting in version 9.6.0-alpha.21 and 8.6.45, a depth limit for query condition operator nesting has been added via the `requestComplexity.queryDepth` server option. The option is disabled by default to avoid a breaking change. To mitigate, upgrade and set the option to a value appropriate for your app. No known workarounds are available.