CVE-2026-73421 PUBLISHED

NextAuth.js: Configuration errors can cause existence-based auth checks to fail open (auth object populated with an error)

Assigner: GitHub_M
Reserved: 12.08.2026 Published: 13.08.2026 Updated: 13.08.2026

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.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CVSS Score: 9.1

Product Status

Vendor nextauthjs
Product next-auth
Versions
  • Version >= 5.0.0-beta.4, < 5.0.0-beta.32 is affected

References

Problem Types

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