OpenDJ unauthenticated SSRF, local file read and unbounded-read DoS in the DSMLv2 gateway

Summary

The DSMLv2 SOAP gateway (opendj-dsml-servlet) in OpenIdentityPlatform OpenDJ through 5.1.1 dereferences attacker-supplied xsd:anyURI values server-side without a scheme allowlist, egress filtering, or a size cap, and is reachable without authentication by default. A remote unauthenticated attacker can submit a DSML add/modify request whose value is a URI to (1) perform server-side request forgery against internal services and the cloud metadata endpoint (SSRF), (2) read local files via file: URIs, and (3) exhaust memory through an unbounded response read (DoS). Fixed in 5.1.2: anyURI dereferencing is disabled by default; when enabled it is limited to an http/https allowlist, rejects loopback/link-local/private/reserved targets, refuses HTTP redirects, and caps the bytes read. The gateway also now requires container-managed authentication by default.