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.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-xmf8-cvqr-rfgj Auth.js: getToken() throws an uncaught exception on malformed Bearer authorization headers
Fixes

Solution

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Workaround

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History

Wed, 12 Aug 2026 20:30:00 +0000

Type Values Removed Values Added
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, 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.
Title NextAuth.js: getToken() throws an uncaught exception on malformed Bearer authorization headers
Weaknesses CWE-20
CWE-248
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-12T20:21:11.318Z

Reserved: 2026-08-12T14:32:11.795Z

Link: CVE-2026-73418

cve-icon Vulnrichment

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cve-icon NVD

Status : Received

Published: 2026-08-12T21:17:40.890

Modified: 2026-08-12T21:17:40.890

Link: CVE-2026-73418

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses