laminas-diactoros is a PHP package containing implementations of the PSR-7 HTTP message interfaces and PSR-17 HTTP message factory interfaces. Applications that use Diactoros, and are either not behind a proxy, or can be accessed via untrusted proxies, can potentially have the host, protocol, and/or port of a `Laminas\Diactoros\Uri` instance associated with the incoming server request modified to reflect values from `X-Forwarded-*` headers. Such changes can potentially lead to XSS attacks (if a fully-qualified URL is used in links) and/or URL poisoning. Since the `X-Forwarded-*` headers do have valid use cases, particularly in clustered environments using a load balancer, the library offers mitigation measures only in the v2 releases, as doing otherwise would break these use cases immediately. Users of v2 releases from 2.11.1 can provide an additional argument to `Laminas\Diactoros\ServerRequestFactory::fromGlobals()` in the form of a `Laminas\Diactoros\RequestFilter\RequestFilterInterface` instance, including the shipped `Laminas\Diactoros\RequestFilter\NoOpRequestFilter` implementation which ignores the `X-Forwarded-*` headers. Starting in version 3.0, the library will reverse behavior to use the `NoOpRequestFilter` by default, and require users to opt-in to `X-Forwarded-*` header usage via a configured `Laminas\Diactoros\RequestFilter\LegacyXForwardedHeaderFilter` instance. Users are advised to upgrade to version 2.11.1 or later to resolve this issue. Users unable to upgr…

Affected: Packagist: laminas/laminas-diactoros

### Impact

Applications that use Diactoros, and are either not behind a proxy, or can be accessed via untrusted proxies, can potentially have the host, protocol, and/or port of a `Laminas\Diactoros\Uri` instance associated with the incoming server request modified to reflect values from `X-Forwarded-*` headers. Such changes can potentially lead to XSS attacks (if a fully-qualified URL is used in links) and/or URL poisoning.

### Patches

Any version after 2.11.0.

Starting in laminas/laminas-diactoros 2.11.1, we have added `Laminas\Diactoros\ServerRequestFilter\FilterServerRequestInterface`, which defines the single method `__invoke(Psr\Http\Message\ServerRequestInterface $request): Psr\Http\Message\ServerRequestInterface`. Filters implementing this interface allow modifying and returning a generated `ServerRequest`.

The primary use case of the interface is to allow modifying the generated URI based on the presence of headers such as `X-Forwarded-Host`. When operating behind a reverse proxy, the `Host` header is often rewritten to the name of the node to which the request is being forwarded, and an `X-Forwarded-Host` header is generated with the original `Host` value to allow the server to determine the original host the request was intended for. (We have always examined the `X-Forwarded-Proto` header; as of Diactoros 2.11.1, we also examine the `X-Forwarded-Port` header.) To accommodate this use case, we created Laminas\Diactoros\ServerRequestFilter\FilterUsingXForwardedH…