CVE-2026-55688

Vulnerability in AsyncHttpClient (AHC) library before versions 3.0.13 and 2.16.1 allows cross-host request replay that updates the current request but leaves the target request and proxy context pointing to the original origin. This can send the original host's path, Host header, Authorization credentials, or plaintext request to the replay destination.

The AsyncHttpClient library allows Java applications to execute HTTP requests and asynchronously process HTTP responses. From 2.0.0 until 2.16.1 and 3.0.12, PropertiesBasedResumableProcessor stores resumable download state at the predictable shared path $java.io.tmpdir/ahc/ResumableAsyncHandler.properties with default permissions and link-following file operations. A local user who can read the shared store can see download URLs, including embedded user information or query tokens. A local user who can write within or pre-create the affected shared store directory can plant a symbolic link that the client follows when saving state, truncating and overwriting a target file writable by the client process. The filesystem path is used when ResumableAsyncHandler decorates another AsyncHandler, while the no-argument constructors use a no-op processor and are unaffected. This issue is fixed in versions 2.16.1 and 3.0.12.

The AsyncHttpClient (AHC) library from version 2.1.0 until 3.0.14 does not retain whether a Set-Cookie response used a secure transport. The default ThreadSafeCookieStore accepts Secure cookies received over plaintext and permits insecure cookies to overlay or delete existing Secure cookies with matching scope. An attacker controlling a plaintext same-site response can plant, replace, or remove cookie state later sent to an HTTPS origin.

In the AsyncHttpClient (AHC) library prior to versions 3.0.12 and 2.16.1, a proxied ws request is carried through CONNECT, but NettyRequestFactory.newNettyRequest and requestUri decide whether to attach proxy authentication and an absolute-form target only from whether the URI is secure. Because ws is not marked secure, the tunneled WebSocket upgrade sent to the origin includes the proxy's Proxy-Authorization value. Basic credentials are directly recoverable and Digest responses can be replayed or cracked offline. This issue is fixed in versions 3.0.12 and 2.16.1.

The AsyncHttpClient (AHC) library prior to 3.0.12 and 2.16.1 has a vulnerability in WebSocketHandler.upgrade that aborts a handshake with missing or invalid Sec-WebSocket-Accept but continues into pipeline installation and onOpen delivery. Frames coalesced with the invalid 101 response can be decoded and delivered from a peer that did not prove the handshake, although the request future fails and the channel closes. This issue is fixed in versions 3.0.12 and 2.16.1.

The AsyncHttpClient (AHC) library before versions 3.0.12 and 2.16.1 generates the HTTP Digest client nonce using ThreadLocalRandom instead of a cryptographically secure random source. This makes the authentication mechanism vulnerable to chosen-plaintext and credential precomputation attacks.

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. Prior to 3.0.13 and 2.16.1, the HTTP/1.1 connection-pool key excludes the authenticated principal for connection-oriented NTLM and Negotiate authentication. A pooled socket authenticated for one request can be reused by a request carrying another principal, and the server executes that later request as the first identity. Basic and Digest are not affected because they authenticate each request. This issue is fixed in versions 3.0.13 and 2.16.1.

In the AsyncHttpClient (AHC) library prior to versions 3.0.13 and 2.16.1, ThreadSafeCookieStore validates Domain attributes with domain matching but does not reject public suffixes. A host beneath a suffix such as co.uk can set a cookie for that suffix, after which the shared cookie store sends it to unrelated hosts under the suffix. This can inject or overwrite session-relevant cookie values across origins. This issue is fixed in versions 3.0.13 and 2.16.1.

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. In 3.0.12, a peer offering only Digest qop=auth-int causes mutual-authentication verification to be skipped. AuthenticatorUtils.computeExpectedRspAuth returns no expected value for auth-int, and Interceptors treats that result as unverifiable but nonfatal, so a response with an invalid rspauth value is accepted. A peer that does not know the shared secret can therefore be accepted as the authenticated server. This issue is fixed in version 3.0.13.

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. Prior to 3.0.12 on 3.x and 2.16.1 on 2.x, the client infers that an HTTP proxy tunnel exists from the last request method rather than the CONNECT result. After a proxy rejects CONNECT, redirect or authentication handlers can write an origin request and its Authorization credentials onto the still-plaintext proxy connection. Basic credentials can be recovered directly, while NTLM responses may be cracked or relayed. This issue is fixed in versions 3.0.12 and 2.16.1.