CVE-2026-73418
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk39th percentile - higher than 39% of all known CVEs
Summary
NextAuth.js before @auth/core 0.41.3, next-auth 4.24.15, and 5.0.0-beta.32 can throw an uncaught exception in getToken() when reading a malformed Authorization: Bearer header. When no session cookie is present, getToken() URL-decodes the bearer value before validation, and malformed percent encoding causes decodeURIComponent() to throw. This can lead to per-request denial of service without exposing tokens or bypassing authentication.
Risk Assessment
A single unauthenticated request can trigger an unhandled exception in authentication code, causing temporary unavailability of the application.
Recommendation
Immediately update to @auth/core 0.41.3, next-auth 4.24.15, or 5.0.0-beta.32, which contain the fix.
Other vulnerabilities in NextAuth.js
See all- CVE-2026-73421Critical
NextAuth.js from 5.0.0-beta.0 until 5.0.0-beta.32 has a vulnerability where applications that gate access by checking only for the existence of the auth object can fail open when Auth.js has a server configuration error. A non-OK session response is parsed into a truthy error object instead of null, so checks such as !!auth evaluate to true for unauthenticated requests.
- CVE-2026-73420Critical
NextAuth.js prior to @auth/core 0.41.3 and next-auth 4.24.15 and 5.0.0-beta.32 has a vulnerability in the email normalizer, where an address with a fullwidth at-sign (U+FF20) passes validation but after Unicode normalization becomes a standard @, potentially causing the sign-in link to be delivered to an attacker.
- CVE-2026-73419Medium
NextAuth.js before @auth/core 0.41.3, next-auth 4.24.15, and 5.0.0-beta.32 stores OAuth/OIDC anti-CSRF state, nonce, and PKCE verifier in global cookies not bound to the provider. An attacker can exploit this to link their account to a victim's account in multi-provider apps with account linking.
Original NVD description (English source)
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, the exported getToken() helper in the next-auth/jwt and @auth/core/jwt modules can throw an uncaught exception when it reads a malformed Authorization: Bearer header. When no session cookie is present, getToken() URL-decodes the bearer value before validating it, and malformed percent encoding causes decodeURIComponent() to throw instead of treating the token as invalid. Because getToken() is commonly called in API routes, middleware, and server-side request handlers, a single unauthenticated request can trigger an unhandled exception in code paths that authenticate requests, causing a per-request denial of service without exposing tokens, sessions, or other data and without bypassing authentication. This issue is fixed in @auth/core 0.41.3 and next-auth 4.24.15 and 5.0.0-beta.32.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS