CVE-2026-73419
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.
Scoring
- Severity
- MEDIUM
- CVSS base score
- 6.8
- CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
- EPSS probability
- 0.19%
- CWE
- CWE-345, CWE-346, CWE-940
- Published
- 2026-08-12
- Last modified
- 2026-08-13
Affected products
- nextauthjs next-auth
- nextauthjs next-auth
- @auth core
Weakness type
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