# Undertow OutOfMemory when parsing form data encoding with application/x-www-form-urlencoded

Advisory record · `GHSA-6h4f-pj3g-q8fq`

- **Identifiers:** `GHSA-6h4f-pj3g-q8fq` · `CVE-2024-3884`
- **State:** Confirmed
- **Severity:** CVSS 7.5 High
- **Critical:** No
- **Weakness (CWE):** [CWE-20](https://cwe.mitre.org/data/definitions/20.html)
- **Tags:** [CWE-20](https://agentprime.io/advisories/tag/cwe-20.md)
- **Published:** 3 Dec 2025
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 3 Dec 2025, 21:31 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `io.undertow:undertow-core` (Maven): affected `<2.2.39.Final || >=2.4.0.Alpha1, <2.4.0.Beta1 || >=2.3.0.Alpha1, <2.3.21.Final`; fixed in `2.2.39.Final`, `2.4.0.Beta1`, `2.3.21.Final`

## 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:** 0.015, the 73rd percentile, on 12 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 3 Dec 2025, 18:40 UTC: [Confirmed by the CVE List](https://www.cve.org/CVERecord?id=CVE-2024-3884)
- 3 Dec 2025, 19:15 UTC: [Confirmed by NVD](https://nvd.nist.gov/vuln/detail/CVE-2024-3884)
- 31 Oct 2026, 14:17 UTC: First seen by agentprime
- 31 Oct 2026, 14:17 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-6h4f-pj3g-q8fq)

## Sources

- [GitHub Advisory Database: GHSA-6h4f-pj3g-q8fq](https://github.com/advisories/GHSA-6h4f-pj3g-q8fq)
- [OSV: GHSA-6h4f-pj3g-q8fq](https://osv.dev/vulnerability/GHSA-6h4f-pj3g-q8fq)
- <https://nvd.nist.gov/vuln/detail/CVE-2024-3884>
- <https://github.com/undertow-io/undertow/pull/1894>
- <https://github.com/undertow-io/undertow/pull/1882>
- <https://github.com/undertow-io/undertow/pull/1860>
- <https://github.com/undertow-io/undertow/pull/1856>
- <https://github.com/undertow-io/undertow/commit/cb854c779b9e2368c3c274ebd7217c8e75d505be>
- <https://github.com/undertow-io/undertow/releases/tag/2.4.0.Beta1>
- <https://github.com/undertow-io/undertow/releases/tag/2.3.21.Final>
- <https://github.com/undertow-io/undertow/releases/tag/2.2.39.Final>
- <https://github.com/undertow-io/undertow>
- <https://bugzilla.redhat.com/show_bug.cgi?id=2275287>
- <https://access.redhat.com/security/cve/CVE-2024-3884>

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-6h4f-pj3g-q8fq>, 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-6h4f-pj3g-q8fq/>. Everything for agents: <https://agentprime.io/llms.txt>.