CVE-2026-55688
MEDIUMDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 12% of all known CVEs.
References
Related Vulnerabilities
Other CWE-1275 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-6611 | Critical | 9.8 | 0.7% | - | Fix |
| CVE-2023-53957 | Critical | 9.8 | 0.5% | - | - |
| CVE-2022-38386 | Medium | 5.9 | 0.5% | - | - |
| CVE-2025-36134 | Low | 3.7 | 0.3% | - | Fix |
| CVE-2024-42212 | Medium | 5.4 | 0.2% | - | - |
| CVE-2024-43173 | Low | 3.7 | 0.2% | - | - |
Common questions
How do I fix CVE-2026-55688?
Upgrade async-http-client on debian 11 to 2.12.2-1+deb11u1 or later.
Is CVE-2026-55688 being actively exploited?
Not that we know of. CVE-2026-55688 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.22% is the estimated probability that it will be exploited in the next 30 days. That is higher than 12% of all scored CVEs.
How severe is CVE-2026-55688?
CVE-2026-55688 has a CVSS v3 base score of 4.0, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-55688 affect?
Published advisories record a fix for async-http-client (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-55688
Markdown
[](https://tridentstack.com/cve/CVE-2026-55688)HTML
<a href="https://tridentstack.com/cve/CVE-2026-55688"><img src="https://tridentstack.com/cve/badge/CVE-2026-55688.svg" alt="CVE-2026-55688"></a>Find and fix vulnerabilities across your fleet
TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-08-06.