CVE-2026-42280 Improper Permission Checking in Auth.js SDK

What is CVE-2026-42280?

CVE-2026-42280 is a high-severity missing authorization vulnerability in auth0.js, published on 27 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Auth0.js is a client-side JavaScript library for Auth0. From 8.11.0 to 9.32.0, under specific preconditions, the Auth0.js SDK may improperly return user profile information using a valid access token when a specifically crafted invalid ID token is provided. This vulnerability is fixed in 10.0.0.

Weakness: CWE-863

Which versions are affected by CVE-2026-42280?

2 open source packages ship an affected version, including auth0-js. It affects 1 product.

Products include Auth0 Auth0.js.

How do I fix CVE-2026-42280?

Upgrade auth0-js to 10.0.0 or later.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-42280 being exploited?

There is no known exploitation of CVE-2026-42280 in the wild and no public exploit code.

Other vulnerabilities in auth0.js

• CVE-2018-6873 Auth bypass in n/a Critical 9.8
• CVE-2018-6874 Cross-Site Request Forgery (CSRF) in Auth0 High 8.8
• CVE-2018-7307 Auth0-js bypasses CSRF checks High 8.8
• CVE-2020-15125 Authorization header is not sanitized in an error object in auth0 High 7.7
• CVE-2017-17068 auth0-js Privilege Escalation Vulnerability High 7.5

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-8qjv-jj2q-x832.