Improper handling of email input in next-auth

Summary

NextAuth.js is a complete open source authentication solution for Next.js applications. An attacker can pass a compromised input to the e-mail signin endpoint that contains some malicious HTML, tricking the e-mail server to send it to the user, so they can perform a phishing attack. Eg.: `balazs@email.com, <a href="http://attacker.com">Before signing in, claim your money!</a>`. This was previously sent to `balazs@email.com`, and the content of the email containing a link to the attacker's site was rendered in the HTML. This has been remedied in the following releases, by simply not rendering that e-mail in the HTML, since it should be obvious to the receiver what e-mail they used: next-auth v3 users before version 3.29.8 are impacted. (We recommend upgrading to v4, as v3 is considered unmaintained. next-auth v4 users before version 4.9.0 are impacted. If for some reason you cannot upgrade, the workaround requires you to sanitize the `email` parameter that is passed to `sendVerificationRequest` and rendered in the HTML. If you haven't created a custom `sendVerificationRequest`, you only need to upgrade. Otherwise, make sure to either exclude `email` from the HTML body or efficiently sanitize it.

Timeline

1. Jul 6, 2022, 6:00 PM UTCCVE published
2. Apr 22, 2025, 3:45 PM UTCCISA SSVC assessment

   Exploitation: poc · Automatable: no · Technical impact: partial

3. Apr 22, 2025, 5:51 PM UTCRecord last updated

Affected versions

• nextauthjs next-auth

  fixed in 3.29.8; From 4.0.0 · fixed in 4.9.0

• next-authnpm

  fixed in 3.29.8

• next-authnpm

  From 4.0.0 · fixed in 4.9.0

References 5