# Undertow vulnerable to Denial of Service (DoS) attacks

Advisory record · `GHSA-339q-62wm-c39w`

- **Identifiers:** `GHSA-339q-62wm-c39w` · `CVE-2021-3859`
- **State:** Confirmed
- **Severity:** CVSS 7.5 High
- **Critical:** No
- **Weakness (CWE):** [CWE-214](https://cwe.mitre.org/data/definitions/214.html) · [CWE-400](https://cwe.mitre.org/data/definitions/400.html) · [CWE-668](https://cwe.mitre.org/data/definitions/668.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md) · [Information disclosure](https://agentprime.io/advisories/tag/info-disclosure.md) · [CWE-214](https://agentprime.io/advisories/tag/cwe-214.md)
- **Published:** 15 Jul 2022
- **Updated:** 22 Feb 2024
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 15 Jul 2022, 21:32 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `io.undertow:undertow-core` (Maven): affected `<2.2.15`; fixed in `2.2.15`

## 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

- 7.5 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** 0.017, the 77th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the GitHub Advisory Database, published 15 Jul 2022. New records show when each source confirmed them.

## Sources

- [GitHub Advisory Database: GHSA-339q-62wm-c39w](https://github.com/advisories/GHSA-339q-62wm-c39w)
- [OSV: GHSA-339q-62wm-c39w](https://osv.dev/vulnerability/GHSA-339q-62wm-c39w)
- <https://nvd.nist.gov/vuln/detail/CVE-2021-3859>
- <https://github.com/undertow-io/undertow/pull/1296>
- <https://github.com/undertow-io/undertow/commit/db0f5be43f8e2a4b88fbedd2eb6d5a95a29ceaa8>
- <https://github.com/undertow-io/undertow/commit/e43f0ada3f4da6e8579e0020cec3cb1a81e487c2>
- <https://access.redhat.com/security/cve/cve-2021-3859>
- <https://bugzilla.redhat.com/show_bug.cgi?id=2010378>
- <https://github.com/undertow-io/undertow>
- <https://issues.redhat.com/browse/UNDERTOW-1979>
- <https://security.netapp.com/advisory/ntap-20221201-0004>

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 (<https://api.agentprime.io/mcp>), 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: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-339q-62wm-c39w>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-339q-62wm-c39w/>. Everything for agents: <https://agentprime.io/llms.txt>.