A StackOverflowError can be raised when parsing a malformed crafted message due to an infinite recursion.
Users should upgrade to 4.1.86.Final.
There is no workaround, except using a custom HaProxyMessageDecoder.
When parsing a TLV with type = PP2TYPESSL, the value can be again a TLV with type = PP2TYPESSL and so on. The only limitation of the recursion is that the TLV length cannot be bigger than 0xffff because it is encoded in an unsigned short type. Providing a TLV with a nesting level that is large enough will lead to raising of a StackOverflowError. The StackOverflowError will be caught if HAProxyMessageDecoder is used as part of Netty’s ChannelPipeline, but using it directly without the ChannelPipeline will lead to a thrown exception / crash.
If you have any questions or comments about this advisory: * Open an issue in netty