CVE-2026-21712Network attack vector

Process crash via malformed IDN formatting

Published Mar 30, 2026 · Updated Mar 30, 2026

Denial of service in Node.js 24.0.0 through 24.14.0 and 25.0.0 through 25.8.1 allows remote authenticated users to crash the process. The url.format() path fails to reject an IDN containing invalid characters before native node_url.cc processing triggers an assertion failure. Reachability requires application code to pass attacker-influenced URL data to url.format(); the failure terminates only the affected Node.js process.

CVSS severity5.7
Medium
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Node.js 24.0.0 through 24.14.0 and 25.0.0 through 25.8.1 allows remote authenticated users to crash the process. The url.format() path fails to reject an IDN containing invalid characters before native node_url.cc processing triggers an assertion failure. Reachability requires application code to pass attacker-influenced URL data to url.format(); the failure terminates only the affected Node.js process.

The record

CVE
CVE-2026-21712
Published
Mar 30, 2026
Updated
Mar 30, 2026
Vendor
Node.js
Product
Node.js
Classifications
CWE-20, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 30, 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=24.14.0 <=24.14.0
  2. Affected versionversion=25.8.1 <=25.8.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Node.js · Node.jsversion=24.14.0 <=24.14.0; version=25.8.1 <=25.8.1

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
5.7HackerOneCVSS:3.0/AV:N/AC:L/PR:L/UI:R/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.

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

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499.004Endpoint Denial of Service: Application 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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Your stack

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