{"id":"GHSA-x445-f3h2-j279","summary":"Auth.js: OAuth state, nonce, and PKCE check cookies are not bound to the provider that created them","details":"## Summary\n\nAuth.js stores the OAuth/OIDC anti-CSRF checks (`state`, `nonce`, and the PKCE verifier) in global cookies that are not bound to the provider that created them. On callback, a check value minted during a sign-in started with one provider can satisfy the callback for a different provider, because the stored cookie is not verified against the callback provider's identity (provider id, issuer, client id, or redirect URI). In a multi-provider app that allows account linking while logged in, this provider-confusion / mix-up condition can let an attacker link their account at a second provider to a victim's user.\n\n## Am I affected?\n\nYou may be affected if **all** of the following hold:\n\n- You use `next-auth` `\u003c= 4.24.14` or `\u003e= 5.0.0-beta.1, \u003c= 5.0.0-beta.31`, or `@auth/core` `\u003c= 0.41.2`.\n- You configure multiple OAuth/OIDC providers.\n- You allow users to link additional providers while logged in.\n- At least one configured provider's authorization request is observable by an attacker, and at least one target provider's callback can be satisfied without a PKCE verifier (i.e. it relies only on `state` or only on `nonce`).\n\nYou are **not** affected if you use a single OAuth provider, do not allow logged-in account linking, or all providers enforce PKCE.\n\n## Impact\n\n- Account-linking confusion: an attacker can get their account at a target provider linked to the victim's Auth.js user, granting the attacker persistent sign-in to the victim's account through that linked provider.\n- Exploitation requires luring the victim into starting a legitimate same-origin flow; it cannot be performed by cross-site request forgery alone, which reduces practical likelihood.\n\n## Patched version\n\nThe fix binds the OAuth check cookies to the provider/authorization flow that created them, so a callback cannot consume a check value minted for a different provider. Upgrade to the first releases containing this fix (pending; this advisory will be updated with exact patched versions before publication).\n\n## Workarounds\n\nIf you cannot upgrade immediately:\n\n- Enable PKCE (`checks: [\"pkce\"]`, in addition to `state`/`nonce`) on every provider that supports it; PKCE blocks the practical code-swap variant because the attacker cannot observe the relying party's verifier.\n- Avoid offering logged-in account linking across multiple providers where one provider is lower-trust or attacker-observable.\n- Treat `events.linkAccount` as sensitive: add audit logging, user notification, or out-of-band confirmation so that any unexpected link is visible (defense-in-depth, not a root-cause fix).\n\n## Credit\n\nReported by @Nadav0077. Thank you for the responsible disclosure.","aliases":["CVE-2026-73419"],"modified":"2026-08-13T21:00:12.607655523Z","published":"2026-07-23T14:31:51Z","database_specific":{"nvd_published_at":"2026-08-12T21:17:41Z","cwe_ids":["CWE-345","CWE-346","CWE-940"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-07-23T14:31:51Z"},"references":[{"type":"WEB","url":"https://github.com/nextauthjs/next-auth/security/advisories/GHSA-x445-f3h2-j279"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-73419"},{"type":"WEB","url":"https://github.com/nextauthjs/next-auth/pull/13469"},{"type":"WEB","url":"https://github.com/nextauthjs/next-auth/commit/5bca2399a79ba8d116ca5179b4b1ebcd152e7f05"},{"type":"WEB","url":"https://github.com/nextauthjs/next-auth/commit/9f7a97fade9b1319bb9ac19fc9828d62e0a2a852"},{"type":"PACKAGE","url":"https://github.com/nextauthjs/next-auth"},{"type":"WEB","url":"https://github.com/nextauthjs/next-auth/releases/tag/@auth/core@0.41.3"},{"type":"WEB","url":"https://github.com/nextauthjs/next-auth/releases/tag/next-auth@4.24.15"},{"type":"WEB","url":"https://github.com/nextauthjs/next-auth/releases/tag/next-auth@5.0.0-beta.32"}],"affected":[{"package":{"name":"@auth/core","ecosystem":"npm","purl":"pkg:npm/%40auth/core"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.41.3"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 0.41.2","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-x445-f3h2-j279/GHSA-x445-f3h2-j279.json"}},{"package":{"name":"next-auth","ecosystem":"npm","purl":"pkg:npm/next-auth"},"ranges":[{"type":"SEMVER","events":[{"introduced":"5.0.0-beta.1"},{"fixed":"5.0.0-beta.32"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 5.0.0-beta.31","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-x445-f3h2-j279/GHSA-x445-f3h2-j279.json"}},{"package":{"name":"next-auth","ecosystem":"npm","purl":"pkg:npm/next-auth"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.24.15"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 4.24.14","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-x445-f3h2-j279/GHSA-x445-f3h2-j279.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N"}]}