auth0/node-jws Improperly Verifies HMAC Signature

### Overview An improper signature verification vulnerability exists when using auth0/node-jws with the HS256 algorithm under specific conditions. ### Am I Affected? You are affected by this vulnerability if you meet all of the following preconditions: 1. Application uses the auth0/node-jws implementation of JSON Web Signatures, versions <=3.2.2 || 4.0.0 2. Application uses the jws.createVerify() function for HMAC algorithms 3. Application uses user-provided data from the JSON Web Signature Protected Header or Payload in the HMAC secret lookup routines You are NOT affected by this vulnerability if you meet any of the following preconditions: 1. Application uses the jws.verify() interface (note: `auth0/node-jsonwebtoken` users fall into this category and are therefore NOT affected by this vulnerability) 2. Application uses only asymmetric algorithms (e.g. RS256) 3. Application doesn’t use user-provided data from the JSON Web Signature Protected Header or Payload in the HMAC secret lookup routines ### Fix Upgrade auth0/node-jws version to version 3.2.3 or 4.0.1 ### Acknowledgement Okta would like to thank Félix Charette for discovering this vulnerability.

Source published

4 Dec 2025 16:54:15 UTC

Source modified

10 Sep 2026 03:50:31 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Publisher rating · HIGH