CVE-2026-73419

Received Received - Intake

CSRF in NextAuth.js Authentication Flow

Publication date: 2026-08-12

Last updated on: 2026-08-12

Assigner: GitHub, Inc.

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.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-08-12

Last Modified

2026-08-12

Generated

2026-08-13

AI Q&A

2026-08-13

EPSS Evaluated

N/A

NVD

CVE-2026-73419

Affected Vendors & Products

Vendor	Product	Version / Range
authjs	auth.js	to 0.41.3 (exc)
nextauth	next-auth	to 4.24.15 (exc)
nextauth	next-auth	5.0.0-beta.32

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-940	The product establishes a communication channel to handle an incoming request that has been initiated by an actor, but it does not properly verify that the request is coming from the expected origin.
CWE-345	The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
CWE-346	The product does not properly verify that the source of data or communication is valid.

Attack-Flow Graph

Executive Summary

This vulnerability in NextAuth.js affects multi-provider authentication setups. It allows an attacker to link their account to a victim's account by exploiting improperly stored OAuth/OIDC anti-CSRF checks. The stored state, nonce, and PKCE verifier cookies are not bound to the specific provider, enabling cross-provider attacks where a callback from one provider can be satisfied by another provider's credentials.

Impact Analysis

If you use NextAuth.js with multiple authentication providers and allow account linking while logged in, an attacker could gain persistent access to your account. They could trick you into starting a legitimate sign-in flow, then link their account to yours. This grants them ongoing unauthorized access without needing to bypass authentication directly.

Compliance Impact

This vulnerability could lead to unauthorized account access, potentially violating data protection requirements under GDPR (Article 32 security of processing) and HIPAA (access controls). Organizations using affected versions may face compliance violations if user data is exposed due to this flaw.

Mitigation Strategies

Update to patched versions: @auth/core 0.41.3 or next-auth 4.24.15 (v4) or 5.0.0-beta.32 (v5). Disable multi-provider account linking if not required. Monitor for unauthorized account linkages.

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