{"id":"CVE-2022-35924","aliases":["GHSA-xv97-c62v-4587"],"url":"https://o3.security/vulnerability/CVE-2022-35924","summary":"Verification requests (magic link) sent to unwanted emails","details":"### Impact\n`next-auth` users who are using the `EmailProvider` either in versions before `4.10.3` or `3.29.10` are affected.\n\nIf an attacker could forge a request that sent a comma-separated list of emails (eg.: `attacker@attacker.com,victim@victim.com`) to the sign-in endpoint, NextAuth.js would send emails to both the attacker and the victim's e-mail addresses. The attacker could then login as a newly created user with the email being `attacker@attacker.com,victim@victim.com`. This means that basic authorization like `email.endsWith(\"@victim.com\")` in the `signIn` callback would fail to communicate a threat to the developer and would let the attacker bypass authorization, even with an `@attacker.com` address.\n\n### Patches\nWe patched this vulnerability in `v4.10.3` and `v3.29.10` by normalizing the email value that is sent to the sign-in endpoint before accessing it anywhere else. We also added a `normalizeIdentifier` callback on the `EmailProvider` configuration, where you can further tweak your requirements for what your system considers a valid e-mail address. (E.g.: strict RFC2821 compliance)\n\nTo upgrade, run one of the following:\n```sh\nnpm i next-auth@latest\n```\n```sh\nyarn add next-auth@latest\n```\n```sh\npnpm add next-auth@latest\n```\n\n(This will update to the latest v4 version, but you can change `latest` to `3` if you want to stay on v3. This is not recommended. v3 is unmaintained.)\n\n### Workarounds\nIf for some reason you cannot upgrade, you can normalize the incoming request like the following, using Advanced Initialization:\n```ts\n// pages/api/auth/[...nextauth].ts\n\nfunction normalize(identifier) {\n  // Get the first two elements only,\n  // separated by `@` from user input.\n  let [local, domain] = identifier.toLowerCase().trim().split(\"@\")\n  // The part before \"@\" can contain a \",\"\n  // but we remove it on the domain part\n  domain = domain.split(\",\")[0]\n  return `${local}@${domain}`\n}\n\nexport default async function handler(req, res) {\n  if (req.body.email) req.body.email = normalize(req.body.email)\n  return await NextAuth(req, res, {/* your options */ })\n}\n```\n\n### References\n- EmailProvider: https://next-auth.js.org/providers/email\n- Normalize the email address: https://next-auth.js.org/providers/email#normalizing-the-email-address\n- Email syntax: https://en.wikipedia.org/wiki/Email_address#Local-part\n- `signIn` callback: https://next-auth.js.org/configuration/callbacks#sign-in-callback\n- Advanced Initialization: https://next-auth.js.org/configuration/initialization#advanced-initialization\n- `nodemailer` address: https://nodemailer.com/message/addresses\n\n### For more information\n\nIf you have any concerns, we request responsible disclosure, outlined here: https://next-auth.js.org/security#reporting-a-vulnerability\n\n### Timeline\n\nThe issue was reported 26th of July, a response was sent out in less than 1 hour and after identifying the issue a patch was published within 5 working days.\n\n### Acknowledgments\n\nWe would like to thank [Socket](https://socket.dev) for disclosing this vulnerability in a responsible manner and following up until it got published.","published":"2022-08-02T17:55:13Z","modified":"2026-08-12T03:51:35.330684033Z","cvss":{"score":9.1,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"},"epss":{"score":0.01399,"percentile":0.69981,"asOf":"2026-08-23"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"next-auth","fixedVersion":"4.10.3"},{"ecosystem":"npm","name":"next-auth","fixedVersion":"3.29.10"}],"fix":{"url":"https://github.com/nextauthjs/next-auth/commit/afb1fcdae3cc30445038ef588e491d139b916003","label":"nextauthjs/next-auth@afb1fcd"},"references":[{"type":"WEB","url":"https://en.wikipedia.org/wiki/Email_address#Local-part"},{"type":"WEB","url":"https://next-auth.js.org/configuration/callbacks#sign-in-callback"},{"type":"WEB","url":"https://next-auth.js.org/configuration/initialization#advanced-initialization"},{"type":"WEB","url":"https://next-auth.js.org/providers/email"},{"type":"WEB","url":"https://next-auth.js.org/providers/email#normalizing-the-e-mail-address"},{"type":"WEB","url":"https://nodemailer.com/message/addresses"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/35xxx/CVE-2022-35924.json"},{"type":"ADVISORY","url":"https://github.com/nextauthjs/next-auth/security/advisories/GHSA-xv97-c62v-4587"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-35924"},{"type":"FIX","url":"https://github.com/nextauthjs/next-auth/commit/afb1fcdae3cc30445038ef588e491d139b916003"},{"type":"PACKAGE","url":"https://github.com/nextauthjs/next-auth"},{"type":"WEB","url":"https://next-auth.js.org/providers/email#normalizing-the-email-address"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:35.330684033Z"}}