CVE-2026-21713

MediumCVSS 5.9/10Last modified Aug 19, 2026

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 5.9/10CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Weakness enumeration

CWE-208

Affected software

Vendor	Product	Versions
nodejs	node	>= 20.20.1, <= 20.20.1; >= 22.22.1, <= 22.22.1; >= 24.14.0, <= 24.14.0; >= 25.8.1, <= 25.8.1; >= 4.0, < 4.; >= 5.0, < 5.; >= 6.0, < 6.; >= 7.0, < 7.; >= 8.0, < 8.; >= 9.0, < 9.; >= 10.0, < 10.; >= 11.0, < 11.; >= 12.0, < 12.; >= 13.0, < 13.; >= 14.0, < 14.; >= 15.0, < 15.; >= 16.0, < 16.; >= 17.0, < 17.; >= 18.0, < 18.; >= 19.0, < 19.

References

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

Timeline

Published: Mar 30, 2026
Last modified: Aug 19, 2026
NVD status: Analyzed

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