CVE-2026-21713

Name: CVE-2026-21713
Creator: NVD / NIST
Published: 2026-03-30T20:16:19.397+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.9/10EPSS 0.39%

Last modified Jun 17, 2026

This CVE is reserved or awaiting analysis. Details will appear once published by NVD.

Description

A flaw in Node.js HMAC verification uses a non-constant-time comparison when validating user-provided signatures, potentially leaking timing information proportional to the number of matching bytes. Under certain threat models where high-resolution timing measurements are possible, this behavior could be exploited as a timing oracle to infer HMAC values. Node.js already provides timing-safe comparison primitives used elsewhere in the codebase, indicating this is an oversight rather than an intentional design decision. This vulnerability affects **20.x, 22.x, 24.x, and 25.x**.

Metrics

CVSS 3.0

5.9/10

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

0.39%

30.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-208

References

https://nodejs.org/en/blog/vulnerability/march-2026-security-releases

Timeline

Published: Mar 30, 2026
Last Modified: Jun 17, 2026
Status: Awaiting Analysis

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Source: NVD / NIST