The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. Versions on the 2.x branch prior to 2.15.0 and the 3.x branch prior to 3.0.10 leak `Cookie` headers to cross-origin redirect targets. When following a redirect to a different origin, the `propagatedHeaders()` method in `Redirect30xInterceptor.java` strips `Authorization` and `Proxy-Authorization` headers but does not strip the `Cookie` header, causing session cookies and other sensitive cookie values to be sent to attacker-controlled servers. Versions 2.15.0 and 3.0.10 patch the issue.
Async Http Client (aka async-http-client) before 2.0.35 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.