(Netty is an asynchronous, event-driven network application framework. ...)

A flaw was found in netty-codec-http. The WebSocket handshaker in this component fails to properly validate protocol version information during the WebSocket upgrade process. A remote attacker can exploit this vulnerability by manipulating the WebSocket handshake, leading to a bypass of security checks or the negotiation of unexpected protocol versions. This could potentially enable protocol-level attacks.

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, ab attacker can force WebSocket upgrade via the lax V07 (or V08) handshaker by sending `Sec-WebSocket-Version: 7` and omitting `Connection: Upgrade` / `Upgrade: websocket` headers, completing a protocol switch that a proxy would not recognize as an Upgrade request and enabling HTTP request smuggling / protocol-confusion attacks. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.

Netty is an asynchronous, event-driven network application framework. ...

Netty: WebSockets V07/V08 handshaker missing Connection/Upgrade validation