CVE-2026-73421: critical vulnerability in nextauthjs next-auth
NextAuth.js: Configuration errors can cause existence-based auth checks to fail open (auth object populated with an error)
Published · Updated
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28Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 9.1epss 0.6%
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.
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
Affected products
nextauthjs · next-authRelated CVEs — nextauthjs next-auth
In the same product, most dangerous first.
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