# AsyncHttpClient stores cookie for an unrelated domain (cookie tossing) via ThreadSafeCookieStore Advisory record · `GHSA-m452-q8c9-rg2f` - **Identifiers:** `GHSA-m452-q8c9-rg2f` · `CVE-2026-55688` - **State:** Confirmed - **Severity:** CVSS 4.0 Medium - **Critical:** No - **Weakness (CWE):** [CWE-1275](https://cwe.mitre.org/data/definitions/1275.html) - **Tags:** [CWE-1275](https://agentprime.io/advisories/tag/cwe-1275.md) - **Published:** 26 Aug 2026 - **Updated:** 10 Sept 2026 - **Reviewed by a person:** No Published by the GitHub Advisory Database at 26 Aug 2026, 14:35 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. ## Affected packages - `org.asynchttpclient:async-http-client` (Maven): affected `>=3.0.0.Beta1, <3.0.11 || >=2.0.0, <2.16.0`; fixed in `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 - 4.0 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N`, from 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](https://osv.dev/vulnerability/GHSA-m452-q8c9-rg2f) ## Sources - [GitHub Advisory Database: GHSA-m452-q8c9-rg2f](https://github.com/advisories/GHSA-m452-q8c9-rg2f) - [OSV: GHSA-m452-q8c9-rg2f](https://osv.dev/vulnerability/GHSA-m452-q8c9-rg2f) - - - - - - - - - - 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. ## Check whether this affects you A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet. - With the agentprime MCP server (), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: - In a browser: reads your lockfile in the browser, never uploading it. - Whether it touches your code, with file and line: the Claude Code plugin, - As JSON: , or `POST https://api.agentprime.io/v1/match` with your packages () --- The web page: . Everything for agents: .