AsyncHttpClient stores cookie for an unrelated domain (cookie tossing) via ThreadSafeCookieStore
Impact
A cookie tossing / cookie injection issue (CWE-1275). 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 (RFC 6265 §5.3 step 6). 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.
Who is Impacted
Applications that use a single AsyncHttpClient instance - and thus the default, shared CookieStore - to reach both an attacker-influenced host and a trusted host. Typical exposure: crawlers, link-preview / webhook fetchers, SSRF-style "fetch this URL" features, multi-backend aggregators, or following redirects to an attacker-controlled host. The attacker can write a cookie the client presents to the victim host (session fixation, overwriting a session id / CSRF-token cookie); they cannot read the victim host's cookies. Applications that talk only to a fixed trusted backend, or that disable/scope the cookie store, are not exposed.
Patches
Fixed in 3.0.11 and 2.16.0
Workarounds
- Disable the cookie store (setCookieStore(null)) when cookies are not needed; or
- Use a separate AsyncHttpClient (separate cookie store) per trust domain so an attacker-influenced host and a trusted host never share a jar
- Supply a custom CookieStore whose add(Uri, Cookie) rejects cookies whose Domain is not domain-matched by the request host.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.asynchttpclient:async-http-client | >= 3.0.0.Beta1, < 3.0.11, >= 2.0.0, < 2.16.0 | 3.0.11, 2.16.0 |
References
- https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-m452-q8c9-rg2f
- https://nvd.nist.gov/vuln/detail/CVE-2026-55688
- https://github.com/AsyncHttpClient/async-http-client/pull/2196
- https://github.com/AsyncHttpClient/async-http-client/pull/2199
- https://github.com/AsyncHttpClient/async-http-client/commit/8e4069cf3c92abe099db5fb13378ac2fe9e1fd3b
- https://github.com/AsyncHttpClient/async-http-client/commit/e6955c1e3951cf80e286981d064f6c926ce33f47
- https://github.com/AsyncHttpClient/async-http-client
- https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-2.16.0
- https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.11
- https://lists.debian.org/debian-lts-announce/2026/08/msg00011.html
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N- Weakness (CWE)
CWE-1275- Platform
- Java / Kotlin (Maven)
- Package
org.asynchttpclient:async-http-client- Disclosed
- 26.08.2026
- Updated
- 11.10.2026 13:20
Sources and licenses
OSV / GitHub Advisory Database - GHSA-m452-q8c9-rg2f - CC BY 4.0
Vulnerability history: org.asynchttpclient:async-http-client
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 18
- First → latest
- 10.2018 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 2
- High 6
- Medium 8
- Low 2
Disclosures per year
- 2018: 1
- 2019: 0
- 2020: 0
- 2021: 0
- 2022: 0
- 2023: 0
- 2024: 1
- 2025: 0
- 2026: 16
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AsyncHttpClient stores cookie for an unrelated domain (cookie tossing) via ThreadSafeCookieStore this entry
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