CVE-2026-21713
Published: Mar 30, 2026
Modified: May 10, 2026
CVSS v3.0
5.9
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**.
| Vendor | Product | Versions |
|---|---|---|
nodejs | node | affected 20.20.1 - <= 20.20.1affected 22.22.1 - <= 22.22.1affected 24.14.0 - <= 24.14.0affected 25.8.1 - <= 25.8.1affected 4.0 - < 4.*+15 more versions |
CVSS v3.0 Details
CVSS v3.0 Vector
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
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