Async Http Client

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 2.0.0 until 2.16.1 and 3.0.12, automatic response decompression on the HTTP/1.1 path uses ChannelManager.newHttpContentDecompressor() to install Http1ContentDecompressor without a cumulative output-size limit. A hostile or compromised server, or an attacker who can alter a response in transit, can send a small gzip, deflate, or snappy response that expands across chunks until the client exhausts its heap and raises OutOfMemoryError; brotli and zstd are also affected when their optional codecs are present. In versions 3.0.8 through 3.0.10, the HTTP/2 decompressor is also unbounded, so switching protocols does not mitigate the issue on those releases. A limit applied to each decode call is insufficient because the response can be delivered as many small chunks, so the fixed implementation tracks total decompressed bytes for the whole response. This issue is fixed in versions 2.16.1 and 3.0.12.

Published: 2026-09-17T15:55:32.018Z
Updated: 2026-09-17T17:22:22.088Z

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 3.0.8 until 3.0.12, a client with maxConnections or maxConnectionsPerHost set above zero leaks one connection permit whenever TLS connection establishment fails before the handshake completes. NettyConnectListener removes the partitionKeyLock permit from NettyResponseFuture before every failure path is bound to the channel closeFuture, so an abort can leave the permit unreleased. Repeated failures can permanently lock out one host under a per-host limit or drain the shared pool under a global limit, blocking later requests even when no connection remains open. The default unlimited connection setting is not affected. This issue is fixed in version 3.0.12.

Published: 2026-09-17T15:58:40.719Z
Updated: 2026-09-17T16:40:07.831Z

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 2.1.0 until 2.16.1 and 3.0.12, requests using an authenticated SOCKS proxy can expose the proxy's credentials to the origin because NettyRequestFactory and NettyRequestSender attach Proxy-Authorization without confirming that the request is being sent to an HTTP proxy. With preemptive proxy authentication, the header is attached to a plaintext HTTP request, exposing credentials such as directly reversible Basic credentials to the origin. With the default non-preemptive flow, a hostile origin can return a 407 response and ProxyUnauthorized407Interceptor sends the proxy credentials through the existing SOCKS tunnel, including NTLM, Kerberos, and SPNEGO credentials. Releases before 2.1.0 lack SOCKS proxy support. This issue is fixed in versions 2.16.1 and 3.0.12.

Published: 2026-09-17T15:52:16.315Z
Updated: 2026-09-18T14:45:01.238Z

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 2.0.0 until 2.16.1 and 3.0.12, a request using an HTTP proxy to reach an HTTPS origin can expose preemptive origin credentials because NettyRequestFactory and NettyRequestSender.sendRequestWithNewChannel attach Authorization to the plaintext CONNECT request before the TLS tunnel exists. Basic or Digest credentials and per-connection NTLM, Kerberos, or SPNEGO tokens intended for the origin are therefore visible to the proxy and to observers on the client-to-proxy hop. The tunneled request still receives origin Authorization after the tunnel is established, while Proxy-Authorization remains on CONNECT for its intended proxy recipient. This issue is fixed in versions 2.16.1 and 3.0.12.

Published: 2026-09-17T16:00:01.615Z
Updated: 2026-09-21T20:52:24.486Z

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 3.0.8 until 3.0.12, processScramAuthenticationInfo and processAuthenticationInfo compute the SCRAM ServerSignature or Digest rspauth verification result but log a mismatch and still deliver the response as authenticated. On a non-TLS or compromised transport, a peer that has not proved knowledge of the shared secret can therefore be accepted as the server. The fix rejects a present invalid value and computes Digest rspauth from the Authorization parameters actually sent, but verification remains unenforced when the value is absent, the sent parameters cannot be recovered, or Digest uses qop=auth-int. This issue is fixed in version 3.0.12.

Published: 2026-09-17T16:23:27.343Z
Updated: 2026-09-18T14:44:54.072Z