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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.8 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

EPSS

• CVE-2026-73419: 0.25% estimated exploitation activity in the next 30 days; percentile 16.31 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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…

Published by the source

23 Jul 2026, 14:31 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 13:01 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-x445-f3h2-j279

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-x445-f3h2-j279

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# Patch Next advisory brief: CVE-2026-73419

Advisory: Auth.js: OAuth state, nonce, and PKCE check cookies are not bound to the provider that created them
IDs: CVE-2026-73419, GHSA-x445-f3h2-j279
Record: https://patchnext.com/advisories/cve-2026-73419 (revision 2, source checked 26 Oct 2026, 13:01 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @auth/core 0.41.3; next-auth 5.0.0-beta.32, 4.24.15. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @auth/core: affected <= 0.41.2; fixed in 0.41.3
- npm next-auth: affected >= 5.0.0-beta.1, <= 5.0.0-beta.31; <= 4.24.14; fixed in 5.0.0-beta.32, 4.24.15

## Suggested inspection (read-only)
- `npm ls @auth/core --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls next-auth --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @auth/core, next-auth.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-x445-f3h2-j279 (OSV record GHSA-x445-f3h2-j279 lists affected ranges: npm @auth/core >=0 =5.0.0-beta.1 =0 <4.24.15 (fixed))
- Verified: https://github.com/advisories/GHSA-x445-f3h2-j279 (GitHub-reviewed advisory GHSA-x445-f3h2-j279 lists affected ranges: npm @auth/core >=0 =5.0.0-beta.1 =0 <=4.24.14)

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