Summary Five independent HTTP/1.1 conformance laxities in blaze's hand-written Java parser ("http/src/main/java/org/http4s/blaze/http/parser/") cause request-boundary disagreement with a stricter intermediary. All are reachable from a default "BlazeServerBuilder" with no non-default configuration. Impact Actual exploitability depends on the fronting proxy — a boundary disagreement requires a pair of parsers that disagree. Where the proxy forwards the malformed bytes and derives a different message boundary, the consequences are the standard set: front-end ACL/auth bypass, response-queue poisoning on pooled backend connections, and cache poisoning. Risk concentrates on lenient or legacy intermediaries. Workarounds Deploy behind an RFC-strict reverse proxy (nginx, HAProxy, Envoy, ALB) that rejects or re-serializes malformed requests at the edge; this neutralizes most of these for deployments that cannot upgrade immediately.