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Vulnerability record · CVE-2015-9235 · published 29 May 2018

CVE-2015-9235: Auth0 jsonwebtoken improper input validation vulnerability

Auth0 · Jsonwebtoken

In jsonwebtoken node module before 4.2.2 it is possible for an attacker to bypass verification when a token digitally signed with an asymmetric key (RS/ES family) of algorithms but instead the attacker send a token digitally signed with a symmetric algorithm (HS* family).

9.8 CVSS 3.0 Critical EPSS 8.7% · top 5.1% CWE-20 · Improper input validationCWE-327 · Broken cryptographic algorithm
9.8CVSS 3.0 base score, v2 7.5
8.7%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

In jsonwebtoken node module before 4.2.2 it is possible for an attacker to bypass verification when a token digitally signed with an asymmetric key (RS/ES family) of algorithms but instead the attacker send a token digitally signed with a symmetric algorithm (HS* family).

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://auth0.com/blog/2015/03/31/critical-vulnerabilities-in-json-web-token-libraries/ Broken LinkVendor Advisory
https://github.com/auth0/node-jsonwebtoken/commit/1bb584bc382295eeb7ee8c4452a673a77a68b687 PatchThird Party Advisory
https://nodesecurity.io/advisories/17 Third Party Advisory
https://www.timmclean.net/2015/02/25/jwt-alg-none.html ExploitThird Party Advisory
https://auth0.com/blog/2015/03/31/critical-vulnerabilities-in-json-web-token-libraries/ Broken LinkVendor Advisory
https://github.com/auth0/node-jsonwebtoken/commit/1bb584bc382295eeb7ee8c4452a673a77a68b687 PatchThird Party Advisory
https://nodesecurity.io/advisories/17 Third Party Advisory
https://www.timmclean.net/2015/02/25/jwt-alg-none.html ExploitThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2015-9235), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.