Mojolicious is a real-time web framework for Perl. Prior to 9.47, the pure-Perl implementation of Mojo::JSON does not limit nesting depth when Cpanel::JSON::XS is unavailable or MOJO_NO_JSON_XS is enabled. An attacker who can supply untrusted JSON to decode_json, from_json, or j can submit deeply nested arrays or objects, causing unbounded recursion, memory exhaustion, and a process crash. Applications using the Cpanel::JSON::XS backend are not affected because that backend already enforces a nesting limit. This issue is fixed in version 9.47.