On JRuby, the `NONET` parse option fails to block external DTDs or entities when the system identifier uses a short-form IPv4 host (e.g., `http://127.1/`) or an absolute path (e.g., `/x.dtd`) resolved against a network URL. When an application parses untrusted XML using `DTDLOAD`, `DTDVALID`, or `NOENT`, the resolver may treat these identifiers as local and initiate a network request, potentially enabling server-side request forgery (SSRF), which is a technique used to induce a server to make requests to an unintended location.