nextauthjs next-auth up to 5.0.0-beta.31 Session Parsing improper authorization

CVSS Meta Temp Score
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CTI Interest Score
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7.0$0-$5k1.51

Summaryinfo

A vulnerability described as critical has been identified in nextauthjs next-auth up to 5.0.0-beta.31. Affected by this issue is the function auth of the component Session Parsing. The manipulation results in improper authorization. This vulnerability is known as CVE-2026-73421. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in nextauthjs next-auth up to 5.0.0-beta.31. It has been classified as critical. Affected is the function auth of the component Session Parsing. The manipulation with an unknown input leads to a improper authorization vulnerability. CWE is classifying the issue as CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

NextAuth.js provides authentication for Next.js. From next-auth 5.0.0-beta.0 until 5.0.0-beta.32, applications that gate access by checking only for the existence of the auth object returned by the auth() wrapper can fail open when Auth.js has a server configuration error. In middleware, Route Handlers, React Server Components, and other auth() entry points, a non-OK session response is parsed into a truthy error object instead of null, so checks such as !!auth and if (req.auth) evaluate to true for unauthenticated requests. A provider missing both the issuer and authorization endpoint triggers InvalidEndpoints, and an unset AUTH_SECRET or another server configuration error can produce the same behavior. There is no impact while configuration is valid, but after a deployment becomes misconfigured, routes protected only by session existence silently grant access to every visitor. This issue is fixed in next-auth 5.0.0-beta.32.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-73421 since 08/12/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1548.002.

Upgrading to version 5.0.0-beta.32 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper authorization
CWE: CWE-285 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: next-auth 5.0.0-beta.32

Timelineinfo

08/12/2026 CVE reserved
08/13/2026 +1 days VulDB entry created
08/14/2026 +0 days Advisory disclosed
08/14/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-73421 (🔒)
GCVE (CVE): GCVE-0-2026-73421
GCVE (VulDB): GCVE-100-389940

Entryinfo

Created: 08/14/2026 00:41
Changes: 08/14/2026 00:41 (56)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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