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.
Advisories
Source ID Title
Debian DLA Debian DLA DLA-4721-1 async-http-client security update
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 29 Jul 2026 15:00:00 +0000

Type Values Removed Values Added
First Time appeared Asynchttpclient Project
Asynchttpclient Project async-http-client
Vendors & Products Asynchttpclient Project
Asynchttpclient Project async-http-client

Wed, 08 Jul 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-346
References
Metrics threat_severity

None

threat_severity

Moderate


Thu, 02 Jul 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 01 Jul 2026 20:00:00 +0000

Type Values Removed Values Added
Description 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.
Title AsyncHttpClient: Cookie stored for an unrelated domain (cookie tossing) via ThreadSafeCookieStore
Weaknesses CWE-1275
References
Metrics cvssV3_1

{'score': 4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-06T21:56:13.231Z

Reserved: 2026-06-17T00:13:10.650Z

Link: CVE-2026-55688

cve-icon Vulnrichment

Updated: 2026-07-02T14:38:55.557Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-07-01T20:17:11.273

Modified: 2026-08-06T22:17:52.347

Link: CVE-2026-55688

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-07-01T19:40:12Z

Links: CVE-2026-55688 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-01T22:45:03Z

Weaknesses