# undici vulnerable to Denial of Service via unbounded decompression of compressed responses

Advisory record · `GHSA-3xpg-4rpp-hhhm`

- **Identifiers:** `GHSA-3xpg-4rpp-hhhm` · `CVE-2026-84890`
- **State:** Confirmed
- **Severity:** CVSS 5.9 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-770](https://cwe.mitre.org/data/definitions/770.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md)
- **Published:** 29 Sept 2026
- **Updated:** 29 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 29 Sept 2026, 18:20 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `undici` (npm): affected `>=7.15.0, <7.29.1 || >=8.0.0, <8.10.2`; fixed in `7.29.1`, `8.10.2`

## 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

- 5.9 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`, from CNA (openjs)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0041, the 36th percentile, on 13 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 4 Sept 2026, 14:21 UTC: [Published by the maintainers as a GitHub repository advisory](https://github.com/nodejs/undici/security/advisories/GHSA-3xpg-4rpp-hhhm)
- 31 Oct 2026, 13:34 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-3xpg-4rpp-hhhm)

## Sources

- [GitHub Advisory Database: GHSA-3xpg-4rpp-hhhm](https://github.com/advisories/GHSA-3xpg-4rpp-hhhm)
- [OSV: GHSA-3xpg-4rpp-hhhm](https://osv.dev/vulnerability/GHSA-3xpg-4rpp-hhhm)
- <https://github.com/nodejs/undici/security/advisories/GHSA-3xpg-4rpp-hhhm>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-84890>
- <https://github.com/nodejs/undici/commit/2c7d7e1227043c644c4c32cfd1e276f4fd4fcb11>
- <https://github.com/nodejs/undici/commit/7aac7f12f757844763c8b8f1ab6e305e80d55838>
- <https://cna.openjsf.org/security-advisories.html>
- <https://github.com/nodejs/undici>
- <https://github.com/nodejs/undici/releases/tag/v7.29.1>
- <https://github.com/nodejs/undici/releases/tag/v8.10.2>

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-3xpg-4rpp-hhhm>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-3xpg-4rpp-hhhm/>. Everything for agents: <https://agentprime.io/llms.txt>.