GHSA-w6rq-6h34-vh7q Cached redirect poisoning via X-Forwarded-Host header

• Maven io.ratpack:ratpack-core: < 1.9.0 → fixed in 1.9.0

A user supplied `X-Forwarded-Host` header can be used to perform cache poisoning of a cache fronting a Ratpack server if the cache key does not include the `X-Forwarded-Host` header as a cache key. Users are only vulnerable if they do not configure a custom `PublicAddress` instance. A custom `PublicAddress` can be specified by using ServerConfigBuilder::publicAddress. For versions prior to 1.9.0, by default, Ratpack utilizes an inferring version of `PublicAddress` which is vulnerable. Impact This can be used to perform redirect cache poisoning where an attacker can force a cached redirect to redirect to their site instead of the intended redirect location. Patches As of Ratpack 1.9.0, two changes have been made that mitigate this vulnerability: 1. The default PublicAddress implementation no longer infers the address from the request context, instead relying on the configured bind host/port 2. Relative redirects issued by the application are no longer absolutized; they are passed through as-is Workarounds In production, ensure that ServerConfigBuilder::publicAddress correctly configures the server. References • https://portswigger.net/web-security/web-cache-poisoning