CVE-2026-44452

h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit 8dc37cb, when h2o receives a ClientHello message over TLS or QUIC and it contains a zero-length SNI extension, the h2o server runs over the zero-length hostname while trying to copy the hostname, assuming that it ...

PT-2026-60603

Name of the Vulnerable Software and Affected Versions h2o versions prior to commit 8dc37cb Description An issue exists when the server receives a ClientHello message over TLS or QUIC containing a zero-length SNI Server Name Indication extension. The server incorrectly assumes the hostname is...