CVE-2026-21713
MEDIUM
5,9
Source: [email protected]
Attack Vector: network
Attack Complexity: high
Privileges Required: none
User Interaction: none
Scope: unchanged
Confidentiality: high
Integrity: none
Availability: none
Description
AI Translation Available
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**.
https://nodejs.org/en/blog/vulnerability/march-2026-security-releases