CVE-2023-48309

MEDIUM

next-auth < 4.24.5 - Improper Authorization via Middleware JWT Manipulation

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2023-48309. PoCs published by dastaj.

AI-analyzed exploit summary The repository provides a detailed technical analysis and proof-of-concept steps for CVE-2023-48309, an authentication bypass vulnerability in NextAuth.js. It includes step-by-step instructions for exploiting the vulnerability by manipulating cookie names to bypass authentication.

Description

NextAuth.js provides authentication for Next.js. `next-auth` applications prior to version 4.24.5 that rely on the default Middleware authorization are affected by a vulnerability. 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). `next-auth` `v4.24.5` contains a patch for the vulnerability. As a workaround, using a custom authorization callback for Middleware, developers can manually do a basic authentication.

Exploits (1)

github WRITEUP 2 stars
by dastaj · poc
https://github.com/dastaj/CVEs/tree/main/CVE-2023-48309

The repository provides a detailed technical analysis and proof-of-concept steps for CVE-2023-48309, an authentication bypass vulnerability in NextAuth.js. It includes step-by-step instructions for exploiting the vulnerability by manipulating cookie names to bypass authentication.

Classification
Writeup 90%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Reliable
Target: NextAuth.js prior to v4.24.5
No auth needed
Prerequisites: Access to the target application · Ability to manipulate cookies
devstral-2 · analyzed Feb 27, 2026 Full analysis →

Scores

CVSS v3 5.3
EPSS 0.0029
EPSS Percentile 53.3%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-285 CWE-863
Status published
Products (2)
nextauth.js/next-auth < 4.24.5
npm/next-auth 0 - 4.24.5npm
Published Nov 20, 2023
Tracked Since Feb 18, 2026