CVE-2026-73421
NextAuth.js: Configuration errors can cause existence-based auth checks to fail open (auth object populated with an error)
Description
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.
INFO
Published Date :
Aug. 13, 2026, 10:17 p.m.
Last Modified :
Aug. 13, 2026, 10:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-73421
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | CRITICAL | [email protected] |
Solution
- Update next-auth to version 5.0.0-beta.32.
- Ensure proper server configuration for Auth.js.
- Validate authentication checks for robustness.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-73421.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-73421 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-73421
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-73421 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-73421 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Aug. 13, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'nextauthjs', 'product': 'next-auth', 'versions': [{'status': 'affected', 'version': '>= 5.0.0-beta.4, < 5.0.0-beta.32'}]}] Added Description 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. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-285 Added CWE CWE-636 Added Reference https://github.com/nextauthjs/next-auth/commit/d008b9b764bf4b322a87e1822d1dda7789258d8f Added Reference https://github.com/nextauthjs/next-auth/releases/tag/[email protected] Added Reference https://github.com/nextauthjs/next-auth/security/advisories/GHSA-8fpg-xm3f-6cx3