CVE-2026-42280Network attack vector

Profile disclosure via invalid HS256 ID token

Published May 27, 2026 · Updated May 27, 2026

Incorrect authorization in Auth0.js 8.11.0 through 9.32.0 allows remote authenticated users to read user profile data. In validateAuthenticationResponse, an invalid HS256 ID token is decoded and, after its nonce matches, the SDK calls userInfo with the valid access token and returns the profile instead of rejecting the ID token. The path requires a valid access token, HS256 configuration, and application access control based on Auth0 Actions; it exposes profile data without interrupting service.

CVSS severity7.1
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Auth0.js 8.11.0 through 9.32.0 allows remote authenticated users to read user profile data. In validateAuthenticationResponse, an invalid HS256 ID token is decoded and, after its nonce matches, the SDK calls userInfo with the valid access token and returns the profile instead of rejecting the ID token. The path requires a valid access token, HS256 configuration, and application access control based on Auth0 Actions; it exposes profile data without interrupting service.

The record

CVE
CVE-2026-42280
Published
May 27, 2026
Updated
May 27, 2026
Vendor
Auth0
Product
Auth0.js
Classifications
CWE-863, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 8.11.0 , <= 9.32.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Auth0 · Auth0.jsversion=>= 8.11.0 , <= 9.32.0

Published CVSS scores

7.1GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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