When making any HTTP request, the automatically enabled and self-managed CookieStore (aka cookie jar) will silently replace explicitly defined Cookies with any that have the same name from the cookie jar. For services that operate with multiple users, this can result in one user's Cookie being used for another user's requests.
Versions of Async HTTP Client prior to 1.13.2 is vulnerable to a form of targeted request manipulation called CRLF injection. This vulnerability was the result of insufficient validation of HTTP header field values before sending them to the network. Users is vulnerable if they pass untrusted data into HTTP header field values without prior sanitisation. Common use-cases here might be to place usernames from a database into HTTP header fields. …
This package can be tricked into connecting to a host different from the one extracted by java.net.URI if a'?' character occurs in a fragment identifier. Similar bugs were previously identified in cURL (CVE-2016-8624) and Oracle Java 8 java.net.URL.