GHSA-m452-q8c9-rg2f: org.asynchttpclient:async-http-client (CVE-2026-55688)

Package	Ecosystem	Affected	Fixed in
org.asynchttpclient:async-http-client	Maven	>=3.0.0.Beta1, <3.0.11 \|\| >=2.0.0, <2.16.0	3.0.11, 2.16.0

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Async-http-client versions 3.0.0.Beta1 up to but not including 3.0.11, and 2.0.0 up to but not including 2.16.0, store cookies under a Domain attribute without checking that the responding host may set cookies for that domain. An attacker controlling a host the client connects to can plant a cookie for an unrelated domain, which the client then sends to that domain. Exposure requires one shared client instance reaching both an attacker-influenced host and a trusted host. Upgrade to 3.0.11 or 2.16.0. Alternatively, disable the cookie store or use separate clients per trust domain.

Written 2 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
4.0	Medium	3.1	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0033, the 26th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:16 UTC First seen by agentprime
31 Oct 2026, 14:16 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.