High severityNVD Advisory· Published Jul 6, 2022· Updated Apr 22, 2025

Improper handling of email input in next-auth

CVE-2022-31127

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 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 packages

Versions sourced from the GitHub Security Advisory.

Package	Affected versions	Patched versions
next-authnpm	< 3.29.8	3.29.8
next-authnpm	>= 4.0.0, < 4.9.0	4.9.0

Affected products

Nextauthjs/Next Authv5
Range: < 3.29.8

Patches

ae834f1e08a4

feat(providers): allow styling e-mail through `theme` option (#4841)

https://github.com/nextauthjs/next-authBalázs OrbánJul 5, 2022via ghsa

commit

9 files changed · +127 −169

apps/dev/pages/api/auth/[...nextauth].ts+4 −1 modified

@@ -46,7 +46,10 @@ import BoxyHQSAMLProvider from "next-auth/providers/boxyhq-saml"
 // })
 // const adapter = FaunaAdapter(client)
 export const authOptions: NextAuthOptions = {
-  // adapter,
+  // adapter: {
+  //   getUserByEmail: (email) => ({ id: "1", email, emailVerified: null }),
+  //   createVerificationToken: (token) => token,
+  // } as any,
   providers: [
     // E-mail
     // Start fake e-mail server with `npm run start:email`

docs/docs/configuration/options.md+4 −1 modified

@@ -366,11 +366,14 @@ Changes the color scheme theme of [pages](/configuration/pages) as well as allow
 
 In addition, you can define a logo URL in `theme.logo` which will be rendered above the main card in the default signin/signout/error/verify-request pages, as well as a `theme.brandColor` which will affect the accent color of these pages.
 
+The sign-in button's background color will match the `brandColor` and defaults to `"#346df1"`. The text color is `#fff` by default, but if your brand color gives a weak contrast, correct it with the `buttonText` color option.
+
 ```js
 theme: {
   colorScheme: "auto", // "auto" | "dark" | "light"
   brandColor: "", // Hex color code
-  logo: "" // Absolute URL to image
+  logo: "", // Absolute URL to image
+  buttonText: "" // Hex color code
 }
 ```

docs/docs/providers/email.md+49 −42 modified

@@ -124,67 +124,74 @@ providers: [
 The following code shows the complete source for the built-in `sendVerificationRequest()` method:
 
 ```js
-import nodemailer from "nodemailer"
+import { createTransport } from "nodemailer"
 
-async function sendVerificationRequest({
-  identifier: email,
-  url,
-  provider: { server, from },
-}) {
+async function sendVerificationRequest(params) {
+  const { identifier, url, provider, theme } = params
   const { host } = new URL(url)
-  const transport = nodemailer.createTransport(server)
-  await transport.sendMail({
-    to: email,
-    from,
+  // NOTE: You are not required to use `nodemailer`, use whatever you want.
+  const transport = createTransport(provider.server)
+  const result = await transport.sendMail({
+    to: identifier,
+    from: provider.from,
     subject: `Sign in to ${host}`,
     text: text({ url, host }),
-    html: html({ url, host, email }),
+    html: html({ url, host, theme }),
   })
+  const failed = result.rejected.concat(result.pending).filter(Boolean)
+  if (failed.length) {
+    throw new Error(`Email(s) (${failed.join(", ")}) could not be sent`)
+  }
 }
 
-// Email HTML body
-function html({ url, host, email }: Record<"url" | "host" | "email", string>) {
-  // Insert invisible space into domains and email address to prevent both the
-  // email address and the domain from being turned into a hyperlink by email
-  // clients like Outlook and Apple mail, as this is confusing because it seems
-  // like they are supposed to click on their email address to sign in.
-  const escapedEmail = `${email.replace(/\./g, "&#8203;.")}`
-  const escapedHost = `${host.replace(/\./g, "&#8203;.")}`
-
-  // Some simple styling options
-  const backgroundColor = "#f9f9f9"
-  const textColor = "#444444"
-  const mainBackgroundColor = "#ffffff"
-  const buttonBackgroundColor = "#346df1"
-  const buttonBorderColor = "#346df1"
-  const buttonTextColor = "#ffffff"
+/**
+ * Email HTML body
+ * Insert invisible space into domains from being turned into a hyperlink by email
+ * clients like Outlook and Apple mail, as this is confusing because it seems
+ * like they are supposed to click on it to sign in.
+ *
+ * @note We don't add the email address to avoid needing to escape it, if you do, remember to sanitize it!
+ */
+function html(params: { url: string; host: string; theme: Theme }) {
+  const { url, host, theme } = params
+
+  const escapedHost = host.replace(/\./g, "&#8203;.")
+
+  const brandColor = theme.brandColor || "#346df1"
+  const color = {
+    background: "#f9f9f9",
+    text: "#444",
+    mainBackground: "#fff",
+    buttonBackground: brandColor,
+    buttonBorder: brandColor,
+    buttonText: theme.buttonText || "#fff",
+  }
 
   return `
-<body style="background: ${backgroundColor};">
-  <table width="100%" border="0" cellspacing="0" cellpadding="0">
+<body style="background: ${color.background};">
+  <table width="100%" border="0" cellspacing="20" cellpadding="0"
+    style="background: ${color.mainBackground}; max-width: 600px; margin: auto; border-radius: 10px;">
     <tr>
-      <td align="center" style="padding: 10px 0px 20px 0px; font-size: 22px; font-family: Helvetica, Arial, sans-serif; color: ${textColor};">
-        <strong>${escapedHost}</strong>
-      </td>
-    </tr>
-  </table>
-  <table width="100%" border="0" cellspacing="20" cellpadding="0" style="background: ${mainBackgroundColor}; max-width: 600px; margin: auto; border-radius: 10px;">
-    <tr>
-      <td align="center" style="padding: 10px 0px 0px 0px; font-size: 18px; font-family: Helvetica, Arial, sans-serif; color: ${textColor};">
-        Sign in as <strong>${escapedEmail}</strong>
+      <td align="center"
+        style="padding: 10px 0px; font-size: 22px; font-family: Helvetica, Arial, sans-serif; color: ${color.text};">
+        Sign in to <strong>${escapedHost}</strong>
       </td>
     </tr>
     <tr>
       <td align="center" style="padding: 20px 0;">
         <table border="0" cellspacing="0" cellpadding="0">
           <tr>
-            <td align="center" style="border-radius: 5px;" bgcolor="${buttonBackgroundColor}"><a href="${url}" target="_blank" style="font-size: 18px; font-family: Helvetica, Arial, sans-serif; color: ${buttonTextColor}; text-decoration: none; border-radius: 5px; padding: 10px 20px; border: 1px solid ${buttonBorderColor}; display: inline-block; font-weight: bold;">Sign in</a></td>
+            <td align="center" style="border-radius: 5px;" bgcolor="${color.buttonBackground}"><a href="${url}"
+                target="_blank"
+                style="font-size: 18px; font-family: Helvetica, Arial, sans-serif; color: ${color.buttonText}; text-decoration: none; border-radius: 5px; padding: 10px 20px; border: 1px solid ${color.buttonBorder}; display: inline-block; font-weight: bold;">Sign
+                in</a></td>
           </tr>
         </table>
       </td>
     </tr>
     <tr>
-      <td align="center" style="padding: 0px 0px 10px 0px; font-size: 16px; line-height: 22px; font-family: Helvetica, Arial, sans-serif; color: ${textColor};">
+      <td align="center"
+        style="padding: 0px 0px 10px 0px; font-size: 16px; line-height: 22px; font-family: Helvetica, Arial, sans-serif; color: ${color.text};">
         If you did not request this email you can safely ignore it.
       </td>
     </tr>
@@ -193,8 +200,8 @@ function html({ url, host, email }: Record<"url" | "host" | "email", string>) {
 `
 }
 
-// Email Text body (fallback for email clients that don't render HTML, e.g. feature phones)
-function text({ url, host }: Record<"url" | "host", string>) {
+/** Email Text body (fallback for email clients that don't render HTML, e.g. feature phones) */
+function text({ url, host }: { url: string; host: string }) {
   return `Sign in to ${host}\n${url}\n\n`
 }
 ```

packages/next-auth/src/core/init.ts+1 −0 modified

@@ -62,6 +62,7 @@ export async function init({
       colorScheme: "auto",
       logo: "",
       brandColor: "",
+      buttonText: "",
     },
     // Custom options override defaults
     ...userOptions,

packages/next-auth/src/core/lib/email/signin.ts+2 −1 modified

@@ -10,7 +10,7 @@ export default async function email(
   identifier: string,
   options: InternalOptions<"email">
 ) {
-  const { url, adapter, provider, logger, callbackUrl } = options
+  const { url, adapter, provider, logger, callbackUrl, theme } = options
 
   // Generate token
   const token =
@@ -42,6 +42,7 @@ export default async function email(
       expires,
       url: _url,
       provider,
+      theme,
     })
   } catch (error) {
     logger.error("SEND_VERIFICATION_EMAIL_ERROR", {

packages/next-auth/src/core/routes/signin.ts+1 −10 modified

@@ -37,19 +37,10 @@ export default async function signin(params: {
      * it solves. We treat email addresses as all lower case. If anyone
      * complains about this we can make strict RFC 2821 compliance an option.
      */
-    let email = body?.email?.toLowerCase()
+    const email = body?.email?.toLowerCase()
 
     if (!email) return { redirect: `${url}/error?error=EmailSignin` }
 
-    email = email
-      .split(",")[0]
-      .trim()
-      .replaceAll("&", "&amp;")
-      .replaceAll("<", "&lt;")
-      .replaceAll(">", "&gt;")
-      .replaceAll('"', "&quot;")
-      .replaceAll("'", "&#x27;")
-
     // Verified in `assertConfig`
     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
     const { getUserByEmail } = adapter!

packages/next-auth/src/core/types.ts+1 −0 modified

@@ -217,6 +217,7 @@ export interface Theme {
   colorScheme: "auto" | "dark" | "light"
   logo?: string
   brandColor?: string
+  buttonText?: string
 }
 
 /**

packages/next-auth/src/providers/email.ts+65 −55 modified

@@ -3,6 +3,16 @@ import { createTransport } from "nodemailer"
 import type { CommonProviderOptions } from "."
 import type { Options as SMTPConnectionOptions } from "nodemailer/lib/smtp-connection"
 import type { Awaitable } from ".."
+import type { Theme } from "../core/types"
+
+export interface SendVerificationRequestParams {
+  identifier: string
+  url: string
+  expires: Date
+  provider: EmailConfig
+  token: string
+  theme: Theme
+}
 
 export interface EmailConfig extends CommonProviderOptions {
   type: "email"
@@ -16,13 +26,10 @@ export interface EmailConfig extends CommonProviderOptions {
    * @default 86400
    */
   maxAge?: number
-  sendVerificationRequest: (params: {
-    identifier: string
-    url: string
-    expires: Date
-    provider: EmailConfig
-    token: string
-  }) => Awaitable<void>
+  /** [Documentation](https://next-auth.js.org/providers/email#customizing-emails) */
+  sendVerificationRequest: (
+    params: SendVerificationRequestParams
+  ) => Awaitable<void>
   /**
    * By default, we are generating a random verification token.
    * You can make it predictable or modify it as you like with this method.
@@ -56,78 +63,81 @@ export default function Email(options: EmailUserConfig): EmailConfig {
     type: "email",
     name: "Email",
     // Server can be an SMTP connection string or a nodemailer config object
-    server: {
-      host: "localhost",
-      port: 25,
-      auth: {
-        user: "",
-        pass: "",
-      },
-    },
+    server: { host: "localhost", port: 25, auth: { user: "", pass: "" } },
     from: "NextAuth <no-reply@example.com>",
     maxAge: 24 * 60 * 60,
-    async sendVerificationRequest({
-      identifier: email,
-      url,
-      provider: { server, from },
-    }) {
+    async sendVerificationRequest(params) {
+      const { identifier, url, provider, theme } = params
       const { host } = new URL(url)
-      const transport = createTransport(server)
-      await transport.sendMail({
-        to: email,
-        from,
+      const transport = createTransport(provider.server)
+      const result = await transport.sendMail({
+        to: identifier,
+        from: provider.from,
         subject: `Sign in to ${host}`,
         text: text({ url, host }),
-        html: html({ url, host, email }),
+        html: html({ url, host, theme }),
       })
+      const failed = result.rejected.concat(result.pending).filter(Boolean)
+      if (failed.length) {
+        throw new Error(`Email(s) (${failed.join(", ")}) could not be sent`)
+      }
     },
     options,
   }
 }
 
-// Email HTML body
-function html({ url, host, email }: Record<"url" | "host" | "email", string>) {
-  // Insert invisible space into domains and email address to prevent both the
-  // email address and the domain from being turned into a hyperlink by email
-  // clients like Outlook and Apple mail, as this is confusing because it seems
-  // like they are supposed to click on their email address to sign in.
-  const escapedEmail = `${email.replace(/\./g, "&#8203;.")}`
-  const escapedHost = `${host.replace(/\./g, "&#8203;.")}`
+/**
+ * Email HTML body
+ * Insert invisible space into domains from being turned into a hyperlink by email
+ * clients like Outlook and Apple mail, as this is confusing because it seems
+ * like they are supposed to click on it to sign in.
+ *
+ * @note We don't add the email address to avoid needing to escape it, if you do, remember to sanitize it!
+ */
+function html(params: { url: string; host: string; theme: Theme }) {
+  const { url, host, theme } = params
+
+  const escapedHost = host.replace(/\./g, "&#8203;.")
+
+  // eslint-disable-next-line @typescript-eslint/prefer-nullish-coalescing
+  const brandColor = theme.brandColor || "#346df1"
+  // eslint-disable-next-line @typescript-eslint/prefer-nullish-coalescing
+  const buttonText = theme.buttonText || "#fff"
 
-  // Some simple styling options
-  const backgroundColor = "#f9f9f9"
-  const textColor = "#444444"
-  const mainBackgroundColor = "#ffffff"
-  const buttonBackgroundColor = "#346df1"
-  const buttonBorderColor = "#346df1"
-  const buttonTextColor = "#ffffff"
+  const color = {
+    background: "#f9f9f9",
+    text: "#444",
+    mainBackground: "#fff",
+    buttonBackground: brandColor,
+    buttonBorder: brandColor,
+    buttonText,
+  }
 
   return `
-<body style="background: ${backgroundColor};">
-  <table width="100%" border="0" cellspacing="0" cellpadding="0">
-    <tr>
-      <td align="center" style="padding: 10px 0px 20px 0px; font-size: 22px; font-family: Helvetica, Arial, sans-serif; color: ${textColor};">
-        <strong>${escapedHost}</strong>
-      </td>
-    </tr>
-  </table>
-  <table width="100%" border="0" cellspacing="20" cellpadding="0" style="background: ${mainBackgroundColor}; max-width: 600px; margin: auto; border-radius: 10px;">
+<body style="background: ${color.background};">
+  <table width="100%" border="0" cellspacing="20" cellpadding="0"
+    style="background: ${color.mainBackground}; max-width: 600px; margin: auto; border-radius: 10px;">
     <tr>
-      <td align="center" style="padding: 10px 0px 0px 0px; font-size: 18px; font-family: Helvetica, Arial, sans-serif; color: ${textColor};">
-        Sign in as <strong>${escapedEmail}</strong>
+      <td align="center"
+        style="padding: 10px 0px; font-size: 22px; font-family: Helvetica, Arial, sans-serif; color: ${color.text};">
+        Sign in to <strong>${escapedHost}</strong>
       </td>
     </tr>
     <tr>
       <td align="center" style="padding: 20px 0;">
         <table border="0" cellspacing="0" cellpadding="0">
           <tr>
-            <td align="center" style="border-radius: 5px;" bgcolor="${buttonBackgroundColor}"><a href="${url}" target="_blank" style="font-size: 18px; font-family: Helvetica, Arial, sans-serif; color: ${buttonTextColor}; text-decoration: none; border-radius: 5px; padding: 10px 20px; border: 1px solid ${buttonBorderColor}; display: inline-block; font-weight: bold;">Sign in</a></td>
+            <td align="center" style="border-radius: 5px;" bgcolor="${color.buttonBackground}"><a href="${url}"
+                target="_blank"
+                style="font-size: 18px; font-family: Helvetica, Arial, sans-serif; color: ${color.buttonText}; text-decoration: none; border-radius: 5px; padding: 10px 20px; border: 1px solid ${color.buttonBorder}; display: inline-block; font-weight: bold;">Sign
+                in</a></td>
           </tr>
         </table>
       </td>
     </tr>
     <tr>
-      <td align="center" style="padding: 0px 0px 10px 0px; font-size: 16px; line-height: 22px; font-family: Helvetica, Arial, sans-serif; color: ${textColor};">
+      <td align="center"
+        style="padding: 0px 0px 10px 0px; font-size: 16px; line-height: 22px; font-family: Helvetica, Arial, sans-serif; color: ${color.text};">
         If you did not request this email you can safely ignore it.
       </td>
     </tr>
@@ -136,7 +146,7 @@ function html({ url, host, email }: Record<"url" | "host" | "email", string>) {
 `
 }
 
-// Email Text body (fallback for email clients that don't render HTML, e.g. feature phones)
-function text({ url, host }: Record<"url" | "host", string>) {
+/** Email Text body (fallback for email clients that don't render HTML, e.g. feature phones) */
+function text({ url, host }: { url: string; host: string }) {
   return `Sign in to ${host}\n${url}\n\n`
 }

packages/next-auth/tests/email.test.ts+0 −59 removed

@@ -1,59 +0,0 @@
-import { createCSRF, handler } from "./lib"
-import EmailProvider from "../src/providers/email"
-
-const originalEmail = "balazs@email.com"
-
-test.each([
-  [originalEmail, `,<a href="example.com">Click here!</a>`],
-  [originalEmail, ""],
-])("Sanitize email", async (emailOriginal, emailCompromised) => {
-  const sendEmail = jest.fn()
-
-  const { secret, csrf } = createCSRF()
-
-  const email = {
-    original: emailOriginal,
-    compromised: `${emailOriginal}${emailCompromised}`,
-  }
-
-  const { res } = await handler(
-    {
-      providers: [EmailProvider({ sendVerificationRequest: sendEmail })],
-      adapter: {
-        getUserByEmail: (email) => ({ id: "1", email, emailVerified: null }),
-        createVerificationToken: (token) => token,
-      } as any,
-      secret,
-    },
-    {
-      prod: true,
-      path: "signin/email",
-      requestInit: {
-        method: "POST",
-        body: JSON.stringify({
-          email: email.compromised,
-          csrfToken: csrf.value,
-        }),
-        headers: { "Content-Type": "application/json", Cookie: csrf.cookie },
-      },
-    }
-  )
-
-  if (!emailCompromised) {
-    expect(res.redirect).toBe(
-      "http://localhost:3000/api/auth/verify-request?provider=email&type=email"
-    )
-    expect(sendEmail).toHaveBeenCalledWith(
-      expect.objectContaining({
-        identifier: email.original,
-        token: expect.any(String),
-      })
-    )
-  } else {
-    expect(res.redirect).not.toContain("error=EmailSignin")
-
-    const emailTo = sendEmail.mock.calls[0][0].identifier
-    expect(emailTo).not.toBe(email.compromised)
-    expect(emailTo).toBe(email.original)
-  }
-})

Vulnerability mechanics

Generated by null/stub on May 9, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.

References

github.com/advisories/GHSA-pgjx-7f9g-9463ghsaADVISORY
nvd.nist.gov/vuln/detail/CVE-2022-31127ghsaADVISORY
github.com/nextauthjs/next-auth/commit/ae834f1e08a4a9915665eecb9479c74c6b039c9cghsax_refsource_MISCWEB
github.com/nextauthjs/next-auth/releases/tag/next-auth%40v4.9.0ghsax_refsource_MISCWEB
github.com/nextauthjs/next-auth/security/advisories/GHSA-pgjx-7f9g-9463ghsax_refsource_CONFIRMWEB
next-auth.js.org/getting-started/upgrade-v4ghsax_refsource_MISCWEB
next-auth.js.org/providers/emailghsax_refsource_MISCWEB

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cvss	0.455
epss	0.000
exploit	0.000
kev	0.000
patch	-0.070
ransomware	0.000