NextAuth.js default redirect callback vulnerable to open redirects
`next-auth` v3 users before version 3.29.2 are impacted. (We recommend upgrading to v4 in most cases. See our migration guide
https://next-auth.js.org/getting-started/upgrade-v4).`next-auth` v4 users before version 4.3.2 are impacted. Upgrading to 3.29.2 or 4.3.2 will patch this vulnerability. If you are not able to upgrade for any reason, you can add a configuration to your `callbacks` option:
```js
// async redirect(url, baseUrl) { // v3
async redirect({ url, baseUrl }) { // v4
// Allows relative callback URLs
if (url.startsWith("/")) return new URL(url, baseUrl).toString()
// Allows callback URLs on the same origin
else if (new URL(url).origin === baseUrl) return url
return baseUrl
}
```
If you already have a `redirect` callback, make sure that you match the incoming `url` origin against the `baseUrl`.