Summary
Description
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.
Am I Affected?
Users are affected if they meet each of the following preconditions:
- Applications built using Auth0.js version between 8.11.0 and 9.32.0
- The application’s access control relies on rules defined in Auth0 Actions.
Affected product and versions
auth0.js SDK v8.11.0 to v9.32.0
Resolution
Upgrade auth0/auth0.js to v10.0.0 or greater.
Acknowledgements
Okta would like to thank Quan Le (@aleister1102) for their discovery and responsible disclosure.
Impact
The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.
CVE-2026-42280 has a CVSS score of 7.1 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (10.0.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-42280? CVE-2026-42280 is a high-severity incorrect authorization vulnerability in auth0-js (npm), affecting versions >= 8.11.0, <= 9.32.0. It is fixed in 10.0.0. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
- How severe is CVE-2026-42280? CVE-2026-42280 has a CVSS score of 7.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of auth0-js are affected by CVE-2026-42280? auth0-js (npm) versions >= 8.11.0, <= 9.32.0 is affected.
- Is there a fix for CVE-2026-42280? Yes. CVE-2026-42280 is fixed in 10.0.0. Upgrade to this version or later.
- Is CVE-2026-42280 exploitable, and should I be worried? Whether CVE-2026-42280 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-42280 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-42280? Upgrade
auth0-jsto 10.0.0 or later.