Affected: Maven: org.eclipse.jetty:jetty-server

#### Summary

Jetty currently accepts HTTP/2 and HTTP/3 requests where the regular Host header and the pseudo-header :authority do not match. As a result, the same request can carry two different host identities through Jetty:

- logic based on `HttpURI` / `Request.getServerName(request)` uses `:authority` - logic based on raw request headers continues to use `Host`

This creates a host/authority confusion condition that can break security assumptions in higher layers.

Jetty already performs an explicit authority/Host consistency check on the HTTP/1.1 path, but equivalent validation is missing on the HTTP/2 and HTTP/3 paths.

#### Security Impact

This issue is not inherently remote code execution, but it can become security-relevant in deployments that rely on the request host for security-sensitive decisions, including:

- host-based access control - virtual host isolation - multi-tenant routing by hostname - login/logout/callback URL construction - reverse proxy and forwarded-header trust chains - auditing, cache keys, and absolute URL generation

Potential consequences include:

- bypass of host-based ACLs - virtual host or tenant isolation failures - incorrect or attacker-influenced redirect/callback targets - inconsistent proxy/downstream interpretation of the original target host - misleading logs and audit records

#### Technical Root Cause

1. On the HTTP/2 and HTTP/3 metadata builder paths:

- `:authority` is parsed separately into authority/URI state - `Host` is…