CVE-2026-73419: @auth Core

Medium severity, CVSS 6.8. EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• @auth Core: before 0.41.3 (fixed in 0.41.3)
• Nextauthjs Next-Auth: before 4.24.15 (fixed in 4.24.15); from 5.0.0-beta.4, before 5.0.0-beta.32 (fixed in 5.0.0-beta.32)

Published 2026-08-12. Last modified 2026-09-09.