CVE-2026-55688

async-http-client: The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process...

CVE-2026-55688 is fixed in 2 products on 1 platform, first by libasync-http-client-java 2.6.0-1ubuntu0.1~esm1, released July 1, 2026. It is not reported as exploited. Patch Radar priority: Routine.

Routine
CVSS
4.0
medium
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0033
26th percentile

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.

Where it's fixed

ProductFixed inFixReleased
Linux
async-http-client · Debian 12.15 (bookworm) 2.12.3-1+deb12u1 DEBIAN-CVE-2026-55688 Jul 1, 2026
libasync-http-client-java · Ubuntu 20.04 LTS (focal) 2.6.0-1ubuntu0.1~esm1 libasync-http-client-java 2.6.0-1ubuntu0.1~esm1 Jul 1, 2026
libasync-http-client-java · Ubuntu 22.04.1 LTS (jammy) 2.12.3-1ubuntu0.22.04.1 libasync-http-client-java 2.12.3-1ubuntu0.22.04.1 Jul 1, 2026
libasync-http-client-java · Ubuntu 24.04.5 LTS (noble) 2.12.3-1ubuntu0.24.04.1 libasync-http-client-java 2.12.3-1ubuntu0.24.04.1 Jul 1, 2026
libasync-http-client-java · Ubuntu 26.04.1 LTS (resolute) 2.12.3-1ubuntu1.1 libasync-http-client-java 2.12.3-1ubuntu1.1 Jul 1, 2026

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