CVE-2026-34835 Rack: `Rack::Request` accepts invalid Host characters, enabling host allowlist bypass.

Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21, and 3.2.0 to before 3.2.6, Rack::Request parses the Host header using an AUTHORITY regular expression that accepts characters not permitted in RFC-compliant hostnames, including /, ?, , and @. Because req.hos...