HttpObjectDecoder.java in Netty before 4.1.44 allows an HTTP header that lacks a colon, which might be interpreted as a separate header with an incorrect syntax, or might be interpreted as an “invalid fold.”(CVE-2019-20444)
Impact
This vulnerability may result in HTTP request smuggling. When malformed or abnormal HTTP requests are interpreted, the system may interpret them inconsistently, allowing the attacker to ‘smuggle’ a request to one device while the other device is unaware of it.