CVE-2026-73419

Description

NextAuth.js provides authentication for Next.js. Prior to@auth/core 0.41.3 and next-auth 4.24.15 and 5.0.0-beta.32, 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, including the provider ID, issuer, client ID, or redirect URI. In a multi-provider application that permits account linking while logged in, when one provider's authorization request is observable and a target provider callback can be satisfied without a PKCE verifier, an attacker can lure a victim into starting a legitimate same-origin flow and link the attacker's target-provider account to the victim's Auth.js user. The linked provider grants the attacker persistent sign-in to the victim's account, while cross-site request forgery alone is insufficient. This issue is fixed in @auth/core 0.41.3 and next-auth 4.24.15 and 5.0.0-beta.32.

Predictions

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

References

• https://github.com/nextauthjs/next-auth/commit/5bca2399a79ba8d116ca5179b4b1ebcd152e7f05
• https://github.com/nextauthjs/next-auth/commit/9f7a97fade9b1319bb9ac19fc9828d62e0a2a852
• https://github.com/nextauthjs/next-auth/pull/13469
• 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/nextauthjs/next-auth/security/advisories/GHSA-x445-f3h2-j279

CWEs

CWE-345 CWE-346 CWE-940