Mojo::JSON versions before 9.47 for Perl allow memory exhaustion via unbounded recursion in the pure-Perl decoder.

The pure-Perl decode path (decodevalue dispatching to decodearray and decodeobject) recurses with no depth limit, so a small deeply nested JSON document can consume excessive memory.

This path is the default when Cpanel::JSON::XS is not installed or MOJONOJSONXS=1 is set; the Cpanel::JSON::XS fast path is not affected.

Any caller that decodes an untrusted JSON body, for example Mojo::Message::json reached through $c->req->json, can exhaust process memory and cause denial of service.