CVE-2026-55688
Published:July 01, 2026
Updated:August 04, 2026
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.
Affected Packages
https://github.com/AsyncHttpClient/async-http-client.git (GITHUB):
Affected version(s) >=async-http-client-project-2.0.0 <async-http-client-project-2.16.0Fix Suggestion:
Update to version async-http-client-project-2.16.0https://github.com/AsyncHttpClient/async-http-client.git (GITHUB):
Affected version(s) >=async-http-client-project-3.0.0.Beta2 <async-http-client-project-3.0.11Fix Suggestion:
Update to version async-http-client-project-3.0.11org.asynchttpclient:async-http-client (JAVA):
Affected version(s) >=2.0.0 <2.16.0Fix Suggestion:
Update to version 2.16.0org.asynchttpclient:async-http-client (JAVA):
Affected version(s) >=3.0.0.Beta1 <3.0.11Fix Suggestion:
Update to version 3.0.11Related Resources (4)
Do you need more information?
Contact UsCVSS v4
Base Score:
6.3
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
LOW
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
LOW
Subsequent System Availability
NONE
CVSS v3
Base Score:
4
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Weakness Type (CWE)
Sensitive Cookie with Improper SameSite Attribute
EPSS
Base Score:
0.18