In Undertow before versions 7.1.2.CR1, 7.1.2.GA it was found that the fix for CVE-2016-4993 was incomplete and Undertow web server is vulnerable to the injection of arbitrary HTTP headers, and also response splitting, due to insufficient sanitization and validation of user input before the input is used as part of an HTTP header value.

CRLF injection vulnerability in the Undertow web server in WildFly 10.0.0, as used in Red Hat JBoss Enterprise Application Platform (EAP) 7.x before 7.0.2, allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via unspecified vectors.