Echo vs Appsmith

Echo maintains v4 and v5 in parallel and treats security parity as non-negotiable — both of the vulnerabilities in this window were fixed on v5 and backported to v4 within hours. The issues themselves are the same class twice over: values taken from request headers and paths being trusted too readily. Context.Scheme accepted malformed forwarded scheme values, and encoded path separators in static file URLs could bypass route-level middleware and disclose files.

The pattern that matters is where each vulnerability lived: both sat in code that decides what a request is, before any application logic runs, which is where a web framework's security surface actually is. Feature work is confined to v5 — an optional rate-limiter store context for response headers, core hot-path optimisation — while v4 receives security fixes only, a clean maintenance split with no ambiguity about which line is current.

Expect v5 to keep taking the middleware and performance work while v4 continues receiving same-day security backports, and further hardening around path and header parsing given that two reported issues in a row landed there.