CVE-2026-21713 - Vulnerability Details - OpenCVE

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**.

No CVSS v4.0

No CVSS v3.1

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

No data.

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Advisories

Source	ID	Title
Debian DSA	DSA-6183-1	nodejs security update

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References

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

History

Mon, 30 Mar 2026 19:30:00 +0000

Type	Values Removed	Values Added
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.
References		https://nodejs.org/en/blog/vulnerability/march-2026-security-releases
Metrics		cvssV3_0 `{'score': 5.9, 'vector': 'CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N'}`

Projects

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MITRE

Status: PUBLISHED

Assigner: hackerone

Published: 2026-03-30T19:07:28.356Z

Updated: 2026-03-30T19:45:22.905Z

Reserved: 2026-01-04T15:00:06.574Z

Link: CVE-2026-21713

Vulnrichment

No data.

NVD

No data.

Redhat

No data.

OpenCVE Enrichment

No data.

Weaknesses

No weakness.

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