CVE-2026-21713 - GitHub Advisory Database (original) (raw)
A flaw in Node.js HMAC verification uses a non-constant...
Moderate severity Unreviewed PublishedMar 30, 2026 to the GitHub Advisory Database • Updated May 10, 2026
Package
Affected versions
Unknown
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://nvd.nist.gov/vuln/detail/CVE-2026-21713
- https://nodejs.org/en/blog/vulnerability/march-2026-security-releases
Published to the GitHub Advisory Database
Mar 30, 2026
Last updated
May 10, 2026