CVE-2026-93569 — Io.netty/netty-codec-http2: http/1 absolute-form host mismatch is translated to http/2 :authority, overriding the request-target authority
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 …
Published: 2026-09-18 · CVSS: 8.2 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7