CVE-2026-73421

Summary

NextAuth.js provides authentication for Next.js. From next-auth 5.0.0-beta.0 until 5.0.0-beta.32, applications that gate access by checking only for the existence of the auth object returned by the auth() wrapper can fail open when Auth.js has a server configuration error. In middleware, Route Handlers, React Server Components, and other auth() entry points, a non-OK session response is parsed into a truthy error object instead of null, so checks such as !!auth and if (req.auth) evaluate to true for unauthenticated requests. A provider missing both the issuer and authorization endpoint triggers InvalidEndpoints, and an unset AUTH_SECRET or another server configuration error can produce the same behavior. There is no impact while configuration is valid, but after a deployment becomes misconfigured, routes protected only by session existence silently grant access to every visitor. This issue is fixed in next-auth 5.0.0-beta.32.

Affected Software

Weaknesses

• CWE-285: CWE-285: Improper Authorization
• CWE-636: CWE-636: Not Failing Securely ('Failing Open')

References

• https://github.com/nextauthjs/next-auth/security/advisories/GHSA-8fpg-xm3f-6cx3
• https://github.com/nextauthjs/next-auth/commit/d008b9b764bf4b322a87e1822d1dda7789258d8f
• https://github.com/nextauthjs/next-auth/releases/tag/next-auth@5.0.0-beta.32

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