CVE-2026-93569: Inconsistent Interpretation of HTTP Requests

A flaw was found in Netty. A remote unauthenticated attacker can exploit a vulnerability in Netty’s HTTP/1 to HTTP/2 conversion process. When an HTTP/1 request includes both an absolute-form request-target and a conflicting Host header, Netty incorrectly prioritizes the Host header for the HTTP/2 :authority field, discarding the original request-target authority. This inconsistency can allow an attacker to bypass security controls in Netty-based proxies or gateways, potentially leading to unauthorized access, cache poisoning, or misrouting of requests. The netty-all artifact is a shaded jar that embeds the vulnerable HttpConversionUtil class up to and including version 4.1.68; from version 4.1.69 onwards it ships no bytecode and is not affected.