CVE-2023-48309 is a medium-severity (CVSS 5.3) CWE-285 vulnerability in next-auth. A fix is available for next-auth — see the affected versions and patch details below.
next-auth vulnerable to possible user mocking that bypasses basic authentication
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-48309.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
next-authnpmDescription
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@latest
yarn add next-auth@latest
pnpm add next-auth@latest
Workarounds
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | next-auth | all versions | 4.24.5npm install next-auth@4.24.5 |
Affected Products
next-authnextauth.jsDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for next-auth, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update next-auth to 4.24.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-48309 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2023-48309 in your dependencies?
Find it across npm, including transitive dependencies.