---
title: "undici - Denial of Service"
description: "undici HTTP client library for Node.js versions 4.2.1 through 6.29.0, 7.0.0 through 7.30.0, and 8.0.0 through 8.12.1 contains a denial of service caused by unhandled TLS 1.2 renegotiation with mismatched hostname certificates, letting attackers crash the client process, exploit requires attacker-controlled HTTPS endpoint."
url: https://panop.io/threat-heartbeat/CVE-2026-87018/
---

# CVE-2026-87018 undici - Denial of Service

undici HTTP client library for Node.js versions 4.2.1 through 6.29.0, 7.0.0 through 7.30.0, and 8.0.0 through 8.12.1 contains a denial of service caused by unhandled TLS 1.2 renegotiation with mismatched hostname certificates, letting attackers crash the client process, exploit requires attacker-controlled HTTPS endpoint.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-87018)

## Details

Type

Denial Of Service

Impact

Denial Of Service

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Published

15 October 2026

Updated

16 October 2026

Weakness

[CWE-248](https://cwe.mitre.org/data/definitions/248.html)

## Vendor fix

Upgrade to undici 6.29.1, 7.30.1, 8.12.2 or later versions.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-87018](https://nvd.nist.gov/vuln/detail/CVE-2026-87018)
- [https://cna.openjsf.org/security-advisories.html](https://cna.openjsf.org/security-advisories.html)
- [https://github.com/nodejs/undici/security/advisories/GHSA-qrxm-fqhp-jwvm](https://github.com/nodejs/undici/security/advisories/GHSA-qrxm-fqhp-jwvm)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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