Withdrawn by the publisher.

Affected: CleanStart: keycloak

Multiple security vulnerabilities affect the keycloak package. These issues are resolved in later releases. See references for individual vulnerability details.

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty incorrectly parses malformed Transfer-Encoding, enabling request smuggling attacks. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

Affected: Maven: io.netty:netty-codec-http

### Summary Netty incorrectly parses malformed Transfer-Encoding, enabling request smuggling attacks.

### Details Netty incorrectly marks a request as chunked when malformed "Transfer-Encoding: chunked, identity" is present. According to RFC https://datatracker.ietf.org/doc/html/rfc9112#name-message-body-length

" If a Transfer-Encoding header field is present in a request and the chunked transfer coding is not the final encoding, the message body length cannot be determined reliably; the server MUST respond with the 400 (Bad Request) status code and then close the connection. "

A possible scenario is when Netty is behind a proxy that doesn't reject requests with "Transfer-Encoding: chunked, identity", but prefers "Content-Length" and forwards the content to Netty.

### PoC The test below shows Netty successfully parsing the second request, demonstrating how an attacker can smuggle a second request inside a request body.

```java @Test public void test() { String requestStr = "POST / HTTP/1.1\r\n" + "Host: localhost\r\n" + "Transfer-Encoding: chunked, identity\r\n" + "Content-Length: 48\r\n" + "\r\n" + "0\r\n" + "\r\n" + "GET /smuggled HTTP/1.1\r\n" + "Host: localhost\r\n" + "\r\n";

EmbeddedChannel channel = new EmbeddedChannel(new HttpRequestDecoder()); assertTrue(channel.writeInbound(Unpooled.copied…

netty-4.1.133-1.1 on GA media

netty: io.netty/netty-handler-proxy: Netty: HTTP Header Injection via HttpProxyHandler Disabled Validation netty: Netty: High integrity impact due to improper DNS domain name constraint enforcement netty: io.netty/netty-codec-http: Netty: HTTP Request Smuggling due to improper handling of conflicting HTTP/1.0 headers netty: io.netty/netty-codec-http: Netty: Incorrect HTTP response parsing leads to data confusion netty: io.netty/netty-codec-http: Netty: Request smuggling via malformed Transfer-Encoding parsing netty: io.netty/netty-codec-http: io.netty/netty-codec-http2: Netty: Denial of Service via unbounded memory allocation in HTTP content decompression netty-handler: netty-handler: IPv6 subnet rule bypass due to incorrect masking operation netty-handler: Netty: Denial of Service due to eager buffer allocation in TLS handshake netty-resolver-dns: Netty: Information disclosure and data manipulation due to improper CNAME record validation io.netty/netty-resolver-dns: Netty has Insufficient Bailiwick Validation for NS Records netty-handler: Netty: Improper trust manager handling leads to hostname verification bypass

Affected: Ubuntu:Pro:14.04:LTS: netty, Ubuntu:Pro:16.04:LTS: netty, Ubuntu:Pro:18.04:LTS: netty, Ubuntu:Pro:20.04:LTS: netty, Ubuntu:Pro:22.04:LTS: netty, Ubuntu:Pro:24.04:LTS: netty, Ubuntu:25.10: netty, Ubuntu:Pro:26.04:LTS: netty

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty incorrectly parses malformed Transfer-Encoding, enabling request smuggling attacks. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Netty ausnutzen, um Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren, vertrauliche Informationen offenzulegen oder einen Denial-of-Service-Zustand zu verursachen.