chore(deps): update dependency @auth/core to v0.41.3 [security]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
@auth/core (source)	0.41.1 → 0.41.3

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Auth.js: OAuth state, nonce, and PKCE check cookies are not bound to the provider that created them

CVE-2026-73419 / GHSA-x445-f3h2-j279

More information

Details

Summary

Auth.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.

Am I affected?

You may be affected if all of the following hold:

• You use next-auth <= 4.24.14 or >= 5.0.0-beta.1, <= 5.0.0-beta.31, or @auth/core <= 0.41.2.
• You configure multiple OAuth/OIDC providers.
• You allow users to link additional providers while logged in.
• 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).

You are not affected if you use a single OAuth provider, do not allow logged-in account linking, or all providers enforce PKCE.

Impact

• 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.
• 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.

Patched version

The 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).

Workarounds

If you cannot upgrade immediately:

• 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.
• Avoid offering logged-in account linking across multiple providers where one provider is lower-trust or attacker-observable.
• 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).

Credit

Reported by @​Nadav0077. Thank you for the responsible disclosure.

Severity

• CVSS Score: 6.8 / 10 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

References

• https://github.com/nextauthjs/next-auth/security/advisories/GHSA-x445-f3h2-j279
• https://github.com/nextauthjs/next-auth/pull/13469
• https://github.com/nextauthjs/next-auth/commit/5bca2399a79ba8d116ca5179b4b1ebcd152e7f05
• https://github.com/nextauthjs/next-auth/commit/9f7a97fade9b1319bb9ac19fc9828d62e0a2a852
• https://github.com/nextauthjs/next-auth/releases/tag/@auth/core@0.41.3
• https://github.com/nextauthjs/next-auth/releases/tag/next-auth@4.24.15
• https://github.com/nextauthjs/next-auth/releases/tag/next-auth@5.0.0-beta.32
• https://nvd.nist.gov/vuln/detail/CVE-2026-73419
• https://github.com/advisories/GHSA-x445-f3h2-j279

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Auth.js: Email normalizer validates the address before Unicode normalization, allowing a homoglyph @​ bypass

CVE-2026-73420 / GHSA-7rqj-j65f-68wh

More information

Details

Summary

The default email-address normalizer used by the email/magic-link sign-in flow validates the address before applying Unicode normalization. An address can contain a Unicode character that is not an ASCII @ (U+0040) but canonicalizes to one under NFKC/NFKD normalization (the normalization commonly applied by mail libraries and services for internationalized email). Such an address passes the normalizer's single-@ check, but a downstream mail library that normalizes the string then sees two @ separators and may deliver the passwordless sign-in link to a different recipient than intended. This is an instance of validating before canonicalizing.

Am I affected?

You may be affected if all of the following hold:

• You use next-auth >= 4.0.0, < 4.24.14, or @auth/core >= 0.1.0, < 0.41.3.
• You have the email / magic-link (passwordless) provider enabled.
• You rely on the built-in default identifier normalizer (you have not supplied your own normalizeIdentifier).
• Your sendVerificationRequest implementation uses a mail library or delivery service that applies Unicode normalization to recipient addresses (most internationalized-email/SMTPUTF8-capable senders do).

You are not affected if you do not use the email provider, or if your normalizer/mailer rejects or canonicalizes non-ASCII addresses before they are validated.

Impact

• Account takeover: an attacker who knows a victim's email address can request a magic link that is delivered to an attacker-controlled mailbox, then use it to sign in as the victim.
• No victim interaction is required to misroute the link; the attacker initiates the flow.

Patched version

The fix applies Unicode (NFKC) normalization before the address is validated, so homoglyph separators are collapsed and rejected up front. Upgrade to the first release containing this fix (pending; this advisory will be updated with the exact patched version before publication). No application code changes are required after upgrading.

Workarounds

If you cannot upgrade immediately:

• Supply a custom normalizeIdentifier on the email provider that calls identifier.normalize("NFKC") (and lower-cases/trims) before any validation, and rejects addresses that do not contain exactly one @ after normalization.
• Or reject any address whose local part or domain contains non-ASCII characters, if your user base does not require internationalized email addresses.

Credit

Reported by @​kakashi-kx. Thank you for the responsible disclosure.

Severity

• CVSS Score: 9.1 / 10 (Critical)
• Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

References

• https://github.com/nextauthjs/next-auth/security/advisories/GHSA-7rqj-j65f-68wh
• https://github.com/nextauthjs/next-auth/commit/19d2feb24359fa8c79418907fc68d9ec8152ca94
• https://github.com/nextauthjs/next-auth/commit/a63eee12a1a20cb35209e44195b097868517b9a0
• https://github.com/nextauthjs/next-auth/releases/tag/@auth/core@0.41.3
• https://github.com/nextauthjs/next-auth/releases/tag/next-auth@4.24.15
• https://github.com/nextauthjs/next-auth/releases/tag/next-auth@5.0.0-beta.32
• https://github.com/advisories/GHSA-7rqj-j65f-68wh

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Auth.js: getToken() throws an uncaught exception on malformed Bearer authorization headers

CVE-2026-73418 / GHSA-xmf8-cvqr-rfgj

More information

Details

Summary

The exported getToken() helper (next-auth/jwt and @auth/core/jwt) can throw an uncaught exception when it reads a malformed Authorization: Bearer … header. When no session cookie is present, getToken() URL-decodes the bearer value before validating it, and malformed percent-encoding causes the decode step to throw rather than being treated as an invalid token. Because getToken() is commonly called in API routes, middleware, and other request handlers, a single unauthenticated request can trigger an unhandled exception in code paths that authenticate requests.

Am I affected?

You are affected if all of the following hold:

• You use next-auth <= 5.0.0-beta.25 (or @auth/core exposing the same getToken() implementation).
• Your application calls getToken() directly — for example in a Route Handler, middleware, or server-side request handler.
• You do not wrap that getToken() call in your own try/catch.

You are not affected if you only use the framework's auth() helper and never call getToken() yourself, or if every getToken() call site already has its own exception handling.

Impact

• Denial of service: an unauthenticated request carrying a malformed Bearer authorization header can raise an unhandled exception in any handler that calls getToken().
• The impact is per-request and limited to availability; it does not expose tokens, sessions, or other data, and does not bypass authentication.

CWE-20: Improper Input Validation.

Patched version

The fix makes getToken() treat a malformed Bearer value as an invalid token and return null, matching how other undecodable tokens are already handled. Upgrade to the first release containing this fix (to be published; this advisory will be updated with the exact patched version before publication) and no code changes are required.

Workarounds

If you cannot upgrade immediately, either:

• Config/code-level: wrap your getToken() calls so a thrown error is treated as "no token", e.g.

  let token = null
  try {
    token = await getToken({ req, secret })
  } catch {
    token = null
  }

• Or strip/normalize the incoming Authorization header at the edge (proxy, middleware) before it reaches getToken(), rejecting values whose Bearer portion is not valid percent-encoding.

Credit

Reported by @​deprrous. Thank you for the responsible disclosure.

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

• https://github.com/nextauthjs/next-auth/security/advisories/GHSA-xmf8-cvqr-rfgj
• https://github.com/nextauthjs/next-auth/pull/13467
• https://github.com/nextauthjs/next-auth/pull/13469
• https://github.com/nextauthjs/next-auth/commit/5bca2399a79ba8d116ca5179b4b1ebcd152e7f05
• https://github.com/nextauthjs/next-auth/commit/e707770f00c52b3479e43422b0200b059149ed53
• https://github.com/nextauthjs/next-auth/releases/tag/@auth/core@0.41.3
• https://github.com/nextauthjs/next-auth/releases/tag/next-auth@4.24.15
• https://github.com/nextauthjs/next-auth/releases/tag/next-auth@5.0.0-beta.32
• https://nvd.nist.gov/vuln/detail/CVE-2026-73418
• https://github.com/advisories/GHSA-xmf8-cvqr-rfgj

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Release Notes

nextauthjs/next-auth (@​auth/core)

v0.41.3

Compare Source

Bugfixes

• core: getToken() now returns null instead of throwing when the Authorization header contains a malformed Bearer value
• core: OAuth state, nonce, and PKCE check cookies are now bound to the provider that created them and are rejected when a different provider handles the callback
• core: email addresses are Unicode-normalized (NFKC) before validation in the default email normalizer, closing a homoglyph @ bypass

Other

• deps: resolve Dependabot alerts via cross-major dependency upgrades (#​13449)
• deps: resolve Dependabot security advisories via pnpm overrides (#​13441)
• deps: allow nodemailer 8 in peer dependency ranges (#​13434)
• CI formatting and proxy deploy repairs (#​13444)

v0.41.2

Compare Source

Bugfixes

• providers: add issuer to GitHub provider for RFC 9207 compliance (#​13410)

Other

• sync package versions with npm registry (#​13414)

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