CVE-2026-21712

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-03-30 · updated 2026-08-19
Weakness: CWE-20

Description

A flaw in Node.js URL processing causes an assertion failure in native code when `url.format()` is called with a malformed internationalized domain name (IDN) containing invalid characters, crashing the Node.js process.

Affected products

Node.js: from 24.0.0 through 24.14.0; from 25.0.0 through 25.8.1

References

https://hackerone.com/reports/3546390
https://nodejs.org/en/blog/vulnerability/march-2026-security-releases

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