Apicurio/apicurio-registry: apicurio-registry: unhardened saxparser in content-type detection leads to blind xxe / ssrf / billion-laughs dos

A flaw was found in Apicurio Registry. The ContentTypeUtil.isParsableXml() method creates a SAXParserFactory without enabling secure processing features or disabling external entity resolution. An attacker with artifact-write permission (or unauthenticated when the registry runs with default configuration) can upload a crafted XML document to trigger blind server-side request forgery (SSRF) via external DTD/entity fetch, or cause denial of service via entity expansion.