Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-07-01T19:40:12 async-http-client: AsyncHttpClient: Cookie injection allows planting cookies for unrelated domains 4.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N CWE-346

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. In versions from 2.0.0 prior to 2.16.0 and from 3.0.0.Beta1 prior to 3.0.11, ThreadSafeCookieStore stored a cookie under the value of its Domain attribute without verifying that the responding host is allowed to set a cookie for that domain, leading to a cookie tossing / cookie injection issue. A host the client connects to can therefore plant a cookie scoped to an unrelated domain, and the client will then send that cookie on later requests to that domain. Applications that use a single AsyncHttpClient instance - and thus the default, shared CookieStore - to reach both an attacker-influenced host and a trusted host are impacted. This issue has been fixed in versions 2.16.0 and 3.0.11.

A flaw was found in the AsyncHttpClient (AHC) library. The ThreadSafeCookieStore component did not properly verify the domain attribute of cookies, allowing a malicious host to set a cookie for an unrelated domain. This cookie would then be sent by the client in subsequent requests to the targeted domain. This could lead to a cookie injection issue, impacting applications that use a single AsyncHttpClient instance to connect to both untrusted and trusted hosts.

This Moderate impact flaw in the AsyncHttpClient library, affecting Red Hat Enterprise Application Platform, allows a malicious server to inject cookies for unrelated domains. This occurs when an application uses a shared AsyncHttpClient instance to communicate with both untrusted and trusted external services, potentially leading to session hijacking or data manipulation on the trusted domain. Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. Red Hat JBoss Enterprise Application Platform Expansion Pack Under investigation async-http-client Red Hat JBoss Enterprise Application Platform Expansion Pack Under investigation async-http-client-netty-utils https://www.cve.org/CVERecord?id=CVE-2026-55688 https://nvd.nist.gov/vuln/detail/CVE-2026-55688 https://github.com/AsyncHttpClient/async-http-client/pull/2196 https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-m452-q8c9-rg2f