CVE-2026-87018Network attack vectorHinoki check available

Process crash via TLS renegotiation error assertion

Published Oct 15, 2026 · Updated Oct 15, 2026

TLS error handling in Undici allows remote attackers to crash the Node.js process via TLS 1.2 certificate renegotiation. The established-socket error handler treats a renegotiated certificate hostname mismatch as impossible and throws an uncaught assertion in both HTTP/1.1 and HTTP/2 paths. Exploitation requires a connection to an attacker-controlled HTTPS endpoint presenting CA-trusted certificates; TLS 1.3 is unaffected, and the crash interrupts all work in the client process.

CVSS severity7.5
High
EPSS probability0.18%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

TLS error handling in Undici allows remote attackers to crash the Node.js process via TLS 1.2 certificate renegotiation. The established-socket error handler treats a renegotiated certificate hostname mismatch as impossible and throws an uncaught assertion in both HTTP/1.1 and HTTP/2 paths. Exploitation requires a connection to an attacker-controlled HTTPS endpoint presenting CA-trusted certificates; TLS 1.3 is unaffected, and the crash interrupts all work in the client process.

The record

CVE
CVE-2026-87018
Published
Oct 15, 2026
Updated
Oct 15, 2026
Vendor
The Node.js Project
Product
Undici
Classifications
CWE-617, CWE-248, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.2.1 <6.29.1
  2. Affected versionversion=7.0.0 <7.30.1
  3. Affected versionversion=8.0.0 <8.12.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Node.js Project · Undiciversion=4.2.1 <6.29.1; version=7.0.0 <7.30.1; version=8.0.0 <8.12.2

Published CVSS scores

7.5The Node.js ProjectCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-617Reachable Assertion
CWE-248Uncaught Exception
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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