GHSA-VFP3-V2GW-7WFQ Echo: Encoded slash (%2F) bypasses route-level protection and exposes static files

Summary Echo's router and static file handler disagree on URL path decoding. The router matches routes using the raw encoded path preserving %2F as-is, while StaticDirectoryHandler unescapes %2F to / before resolving filesystem paths. This allows an attacker to bypass route-level access controls...