# 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.

- Web page: https://patchblox.com/security/cve/CVE-2026-55688
- Priority: Routine
- CVSS: 4.0 (medium)
- EPSS: 0.0033
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 1, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | async-http-client Debian 12.15 (bookworm) | 2.12.3-1+deb12u1 | [DEBIAN-CVE-2026-55688](https://patchblox.com/security/data/fix/linux/debian-cve-2026-55688.md) | Jul 1, 2026 |
| Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libasync-http-client-java-2.6.0-1ubuntu0.1-esm1.md) | Jul 1, 2026 |
| Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libasync-http-client-java-2.12.3-1ubuntu0.22.04.1.md) | Jul 1, 2026 |
| Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libasync-http-client-java-2.12.3-1ubuntu0.24.04.1.md) | Jul 1, 2026 |
| Linux | libasync-http-client-java Ubuntu 26.04.1 LTS (resolute) | 2.12.3-1ubuntu1.1 | [libasync-http-client-java 2.12.3-1ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libasync-http-client-java-2.12.3-1ubuntu1.1.md) | Jul 1, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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