---
id: CVE-2026-73420
title: NextAuth.js provides authentication for Next.js
summary: >-
  NextAuth.js provides authentication for Next.js. Prior to @auth/core 0.41.3
  and next-auth 4.24.15 and 5.0.0-beta.32, the defaultNormalizer used by the
  email and magic-link sign-in flow validates an address before applying Unicode
  normali…
severity: none
cwe:
  - CWE-180
published: '2026-08-13'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T20:05:53.723'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73420'
references:
  - url: >-
      https://github.com/nextauthjs/next-auth/commit/19d2feb24359fa8c79418907fc68d9ec8152ca94
    label: security-advisories@github.com
  - url: >-
      https://github.com/nextauthjs/next-auth/commit/a63eee12a1a20cb35209e44195b097868517b9a0
    label: security-advisories@github.com
  - url: 'https://github.com/nextauthjs/next-auth/releases/tag/@auth/core@0.41.3'
    label: security-advisories@github.com
  - url: 'https://github.com/nextauthjs/next-auth/releases/tag/next-auth@4.24.15'
    label: security-advisories@github.com
  - url: >-
      https://github.com/nextauthjs/next-auth/releases/tag/next-auth@5.0.0-beta.32
    label: security-advisories@github.com
  - url: >-
      https://github.com/nextauthjs/next-auth/security/advisories/GHSA-7rqj-j65f-68wh
    label: security-advisories@github.com
tags:
  - nvd
epss: 0.00725
epssPercentile: 0.52103
ingestedAt: '2026-09-18T20:51:25.612Z'
---

## Overview

NextAuth.js provides authentication for Next.js. Prior to @auth/core 0.41.3 and next-auth 4.24.15 and 5.0.0-beta.32, the defaultNormalizer used by the email and magic-link sign-in flow validates an address before applying Unicode normalization. An address can contain a Unicode character such as U+FF20 FULLWIDTH COMMERCIAL AT that is not ASCII at-sign but canonicalizes to an ASCII at-sign under NFKC or NFKD normalization. The address passes the normalizer's single-at-sign check, but a downstream sendVerificationRequest mail library or delivery service that normalizes the address can then see two at-sign separators and deliver the passwordless sign-in link to an attacker-controlled recipient. Applications are affected when the email provider uses the built-in normalizer rather than a custom normalizeIdentifier and the downstream sender applies Unicode normalization. An attacker who knows a victim's email address can request the misrouted magic link and sign in as the victim without victim interaction. This issue is fixed in @auth/core 0.41.3 and next-auth 4.24.15 and 5.0.0-beta.32.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.