labstack/echo v5.4.0 on GitHub

Security

This release fixes several security issues. Upgrading is recommended. Some fixes change behavior; read "Behavior changes to check before upgrading" below.

Request scheme: Context.Scheme() now uses the X-Forwarded-Proto, X-Forwarded-Protocol, X-Forwarded-Ssl and X-Url-Scheme headers only when the request comes directly from a loopback, link-local or private network address or a unix socket. Before this, any client could send X-Forwarded-Proto: https over plain HTTP and skip HTTPSRedirect. When X-Forwarded-Proto is present, only it is used (its last value), and the scheme is returned in lowercase. Echo#SchemeExtractor (and Config.SchemeExtractor) selects the strategy: ExtractSchemeFromHeaders(...TrustOption) (default), ExtractSchemeDirect() or LegacySchemeExtractor(). The Secure middleware now sets HSTS based on Context.Scheme(). The Proxy middleware always sets X-Forwarded-Proto from Context.Scheme() and removes X-Forwarded-Ssl, X-Forwarded-Protocol and X-Url-Scheme before forwarding. GHSA-2ffq-g2xg-c22p
Proxy middleware: always sets X-Real-IP from Context.RealIP(), so a client can no longer pass a spoofed X-Real-IP to the upstream. GHSA-99jh-6h7p-pp36
JSONP: Context.JSONP and Context.JSONPBlob accept only a callback that is empty, a JavaScript identifier or a dot-separated path of identifiers (ASCII letters, digits, _ and $). Any other callback returns a 400 Bad Request error that wraps the new ErrInvalidJSONPCallback, and nothing is written. JSONP responses now carry X-Content-Type-Options: nosniff. JSONP lets any website read the response with the user's cookies, so do not use it for data that needs authentication. GHSA-h9g5-28mm-hx3g
MethodOverride: a POST can no longer be overridden to GET, HEAD, OPTIONS, TRACE or CONNECT. Before this, with the MethodFromForm or MethodFromQuery getter and MethodOverride registered with Use before the CSRF middleware, _method=GET skipped the CSRF check. Register MethodOverride with Echo#Pre. GHSA-r7w9-592q-9vg4
Redirects: the trailing slash middlewares and the static directory redirect percent-encode control characters in the redirect path. Before this, /%09/evil.example/ redirected browsers to evil.example. GHSA-v753-g4cw-jm48
Static files: with the default settings, the Static middleware resolves files from the same form of the path that the router matched, so /admin%2Fsecret.txt or /%61dmin/secret.txt can no longer reach a file under a guarded /admin/* route. GHSA-375p-5qhx-8wq4 The Static middleware and StaticDirectoryHandler (used by Echo.Static, Echo.StaticFS, Group.Static and Group.StaticFS) no longer serve paths with a ., .. or empty segment, such as /assets/../admin/secret.txt, also after path unescaping. GHSA-3pmx-cf9f-34xr

Behavior changes to check before upgrading

Proxies or load balancers with public IP addresses. If a proxy connects to your app from a public (or 100.64.0.0/10) address, its X-Forwarded-Proto is now ignored: HTTPSRedirect redirects in a loop and the Secure middleware stops sending HSTS. This affects, for example, Cloudflare, CloudFront and Azure Front Door connecting to a public origin, the GCP external HTTP(S) load balancer including GKE Ingress (35.191.0.0/16, 130.211.0.0/22), and networks that use 100.64.0.0/10 (such as Alibaba Cloud SLB or EKS custom networking). Trust the proxy's address ranges:
```
_, gclb1, _ := net.ParseCIDR("35.191.0.0/16")
_, gclb2, _ := net.ParseCIDR("130.211.0.0/22")
e.SchemeExtractor = echo.ExtractSchemeFromHeaders(echo.TrustIPRange(gclb1), echo.TrustIPRange(gclb2))
```
Proxies on the same host, in a private network (AWS ALB, in-cluster ingress controllers such as ingress-nginx or Traefik, most PaaS routers) or on a unix socket keep working without changes. echo.LegacySchemeExtractor() restores the old behavior but is not safe unless every request passes through a proxy that sets these headers. Serverless adapters or middleware that set RemoteAddr to the client's address also make X-Forwarded-Proto ignored (or, if they take it from a header, spoofable).
Trusted proxies must set X-Forwarded-Proto. A proxy on a trusted address that passes the client's X-Forwarded-Proto through (for example nginx without proxy_set_header X-Forwarded-Proto $scheme;) still lets the client choose the scheme. An invalid X-Forwarded-Proto value now results in http instead of falling back to the other scheme headers.
Your own tests. httptest.NewRequest sets RemoteAddr to 192.0.2.1:1234, which is not trusted, so tests that set X-Forwarded-Proto now see http. Set req.RemoteAddr = "10.0.0.1:1234" or use e.SchemeExtractor = echo.LegacySchemeExtractor() in such tests.
Proxy middleware headers. X-Real-IP sent to the upstream is now always Context.RealIP(). In a chain like nginx → Echo Proxy → upstream, configure Echo#IPExtractor (for example echo.ExtractIPFromRealIPHeader()) to pass the client address on. X-Forwarded-Ssl, X-Forwarded-Protocol and X-Url-Scheme are no longer forwarded; X-Forwarded-Proto carries the scheme.
MethodOverride. Overriding a POST to GET (for example with X-HTTP-Method-Override: GET to send a long query in a POST body) is no longer done; such requests keep the POST method.
Static files. Paths with a double slash or dot segment (for example /assets//app.js) now return 404; in HTML5 mode the index is still served. The Static middleware no longer finds file names that the client sends with non-default escaping (for example %2C, %40 or lowercase hex like %c3%a9) unless StaticConfig.EnablePathUnescaping is set; Echo.Static has behaved this way since v5.2.1. With StaticConfig.EnablePathUnescaping or Config.EnablePathUnescapingStaticFiles, encoded dots (%2e%2e) no longer traverse directories, but encoded slashes are still decoded, so do not combine these options with route-based access control.
JSONP. Context.JSONP returns an error for callbacks that are not JavaScript identifiers.

Documentation

IPExtractor docs: corrected the description of the default (the direct peer address has been used since v5.1.0).
Static middleware: when registered with Echo#Use it runs before route and group middleware, so route guards do not protect the files it serves.