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CVE PROGRAM SOURCE RECORD5.9 Medium

CVE-2026-21713

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

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Status
Published
Published
Updated
Assigning organization
hackerone

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**.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

nodejs node

Default version status: unaffected

  • 20.20.1 to ≤ 20.20.1affected
  • 22.22.1 to ≤ 22.22.1affected
  • 24.14.0 to ≤ 24.14.0affected
  • 25.8.1 to ≤ 25.8.1affected
  • 4.0 to < 4.*affected
  • 5.0 to < 5.*affected
  • 6.0 to < 6.*affected
  • 7.0 to < 7.*affected
  • 8.0 to < 8.*affected
  • 9.0 to < 9.*affected
  • 10.0 to < 10.*affected
  • 11.0 to < 11.*affected
  • 12.0 to < 12.*affected
  • 13.0 to < 13.*affected
  • 14.0 to < 14.*affected
  • 15.0 to < 15.*affected
  • 16.0 to < 16.*affected
  • 17.0 to < 17.*affected
  • 18.0 to < 18.*affected
  • 19.0 to < 19.*affected

References