CVE-2026-21713 | BDVDB-2026-323689 Detail

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**.

Impact#

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Exploit#

History#

1. Version 12026-03-30Record published in the CVE List.
2. Version 22026-05-10Most recent update recorded in the CVE List.