CVE-2022-31127: Improper handling of email input in next-auth

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2022-07-06 · updated 2026-06-17
Weakness: CWE-79

Description

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](https://next-auth.js.org/getting-started/rest-api#post-apiauthsigninprovider) 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.

Affected products

nextauthjs next-auth: before 3.29.8; from 4.0.0 before 4.9.0 — fixed in 3.29.8, 4.9.0

How to fix

Upgrade to a fixed version: nextauthjs next-auth 3.29.8, 4.9.0. Check the vendor advisory for mitigations.

References

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