Possible user mocking that bypasses basic authentication
Impact
next-auth applications prior to version 4.24.5 that rely on the default Middleware authorization are affected.
A bad actor could create an empty/mock user, by getting hold of a NextAuth.js-issued JWT from an interrupted OAuth sign-in flow (state, PKCE or nonce).
Manually overriding the next-auth.session-token cookie value with this non-related JWT would let the user simulate a logged in user, albeit having no user information associated with it. (The only property on this user is an opaque randomly generated string).
This vulnerability does not give access to other users' data, neither to resources that require proper authorization via scopes or other means. The created mock user has no information associated with it (ie. no name, email, access_token, etc.)
This vulnerability can be exploited by bad actors to peek at logged in user states (e.g. dashboard layout).
Note: Regardless of the vulnerability, the existence of a NextAuth.js session state can provide simple authentication, but not authorization in your applications. For role-based access control, you can check out our guide.
Patches
We patched the vulnerability in next-auth v4.24.5. To upgrade, run one of the following:
npm i next-auth@latestyarn add next-auth@latestpnpm add next-auth@latestWorkarounds
Upgrading to latest is the recommended way to fix this issue. However, using a custom authorization callback for Middleware, developers can manually do a basic authentication:
// middleware.ts
import { withAuth } from "next-auth/middleware"
export default withAuth(/*your middleware function*/, {
// checking the existence of any property - besides `value` which might be a random string - on the `token` object is sufficient to prevent this vulnerability
callbacks: { authorized: ({ token }) => !!token?.email }
})References
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | next-auth | < 4.24.5 | 4.24.5 |
References
- https://github.com/nextauthjs/next-auth/security/advisories/GHSA-v64w-49xw-qq89
- https://nvd.nist.gov/vuln/detail/CVE-2023-48309
- https://github.com/nextauthjs/next-auth/commit/d237059b6d0cb868c041ba18b698e0cee20a2f10
- https://authjs.dev/guides/basics/role-based-access-control
- https://github.com/nextauthjs/next-auth
- https://next-auth.js.org/configuration/nextjs#advanced-usage
- https://next-auth.js.org/configuration/nextjs#middlewar
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N- Weakness (CWE)
CWE-285- Platform
- npm
- Package
next-auth- Disclosed
- 20.11.2023
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-v64w-49xw-qq89 - CC BY 4.0
Vulnerability history: next-auth
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 14
- First → latest
- 02.2021 07.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 3
- High 4
- Medium 5
- Low 2
Disclosures per year
- 2021: 1
- 2022: 6
- 2023: 2
- 2024: 0
- 2025: 1
- 2026: 4
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