CVE-2026-73418Network attack vector

Per-request denial of service via malformed Bearer decoding

Published Aug 12, 2026 · Updated Aug 12, 2026

Uncaught exception in @auth/core and NextAuth.js allows remote attackers to interrupt requests via malformed Bearer authorization headers. With no session cookie, getToken() passes the Bearer value to decodeURIComponent() before validation, so malformed percent encoding escapes uncaught. Exposure requires an application to call getToken() directly without exception handling; each request is interrupted without data disclosure or authentication bypass.

CVSS severity7.5
High
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncaught exception in @auth/core and NextAuth.js allows remote attackers to interrupt requests via malformed Bearer authorization headers. With no session cookie, getToken() passes the Bearer value to decodeURIComponent() before validation, so malformed percent encoding escapes uncaught. Exposure requires an application to call getToken() directly without exception handling; each request is interrupted without data disclosure or authentication bypass.

The record

CVE
CVE-2026-73418
Published
Aug 12, 2026
Updated
Aug 12, 2026
Vendor
Auth.js
Product
@auth/core
Classifications
CWE-248, CWE-20, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 0.1.0, < 0.41.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Auth.js · @auth/coreversion=>= 0.1.0, < 0.41.3
Auth.js · NextAuth.jsversion=>= 4.0.6, <= 4.24.14; version=>= 5.0.0-beta.0, <= 5.0.0-beta.31

Published CVSS scores

7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-248Uncaught Exception
CWE-20Improper Input Validation
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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