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
Configurations
No configuration.
History
10 May 2026, 14:16
| Type | Values Removed | Values Added |
|---|---|---|
| CWE | CWE-208 |
01 Apr 2026, 14:24
| Type | Values Removed | Values Added |
|---|---|---|
| Summary |
|
30 Mar 2026, 20:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-03-30 20:16
Updated : 2026-05-10 14:16
NVD link : CVE-2026-21713
Mitre link : CVE-2026-21713
CVE.ORG link : CVE-2026-21713
JSON object : View
Products Affected
No product.
CWE
CWE-208
Observable Timing Discrepancy
