CVE-2026-40155: AUTH0 Nextjs-AUTH0

Medium severity, CVSS 5.4. EPSS: 0.3% chance of exploitation in the next 30 days.

The Auth0 Next.js SDK is a library for implementing user authentication in Next.js applications. In versions 4.12.0 through 4.17.1, simultaneous requests that trigger a nonce retry may cause the proxy cache fetcher to perform improper lookups for the token request results. Users are affected if their project uses both the vulnerable versions and the proxy handler /me/* and /my-org/* with DPoP enabled. This issue has been fixed in version 4.18.0.

Affected products

• AUTH0 Nextjs-AUTH0: from 4.12.0, before 4.18.0 (fixed in 4.18.0)

Published 2026-04-17. Last modified 2026-06-17.