CVE-2026-40155: CWE-863: Incorrect Authorization in auth0 nextjs-auth0
The Auth0 Next.js SDK is a library for implementing user authentication in Next.js applications. In versions 4.12.0 through 4.17.1, simultaneous requests that trigger a nonce retry may cause the proxy cache fetcher to perform improper lookups for the token request results. Users are affected if their project uses both the vulnerable versions and the proxy handler /me/* and /my-org/* with DPoP enabled. This issue has been fixed in version 4.18.0.
AI Analysis
Technical Summary
The Auth0 Next.js SDK versions 4.12.0 to 4.17.1 contain an incorrect authorization flaw (CWE-863) related to handling simultaneous requests that trigger nonce retries. This leads the proxy cache fetcher to perform improper lookups for token request results, potentially exposing token data or allowing unauthorized access. The issue specifically impacts projects using the proxy handler endpoints /me/* and /my-org/* with DPoP enabled. The vulnerability was addressed and fixed in version 4.18.0 of the SDK.
Potential Impact
If exploited, this vulnerability could lead to improper authorization checks resulting in exposure of token information or unauthorized access to user data. The impact is limited to applications using the specified vulnerable versions with the proxy handlers /me/* and /my-org/* and DPoP enabled. There are no known exploits in the wild at this time.
Mitigation Recommendations
Upgrade to Auth0 Next.js SDK version 4.18.0 or later, where this issue has been fixed. Since this is a library vulnerability, applying the official update is the recommended remediation. No other mitigations are indicated by the vendor advisory.
CVE-2026-40155: CWE-863: Incorrect Authorization in auth0 nextjs-auth0
Description
The Auth0 Next.js SDK is a library for implementing user authentication in Next.js applications. In versions 4.12.0 through 4.17.1, simultaneous requests that trigger a nonce retry may cause the proxy cache fetcher to perform improper lookups for the token request results. Users are affected if their project uses both the vulnerable versions and the proxy handler /me/* and /my-org/* with DPoP enabled. This issue has been fixed in version 4.18.0.
CVSS v3.1
Score 5.4medium
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Auth0 Next.js SDK versions 4.12.0 to 4.17.1 contain an incorrect authorization flaw (CWE-863) related to handling simultaneous requests that trigger nonce retries. This leads the proxy cache fetcher to perform improper lookups for token request results, potentially exposing token data or allowing unauthorized access. The issue specifically impacts projects using the proxy handler endpoints /me/* and /my-org/* with DPoP enabled. The vulnerability was addressed and fixed in version 4.18.0 of the SDK.
Potential Impact
If exploited, this vulnerability could lead to improper authorization checks resulting in exposure of token information or unauthorized access to user data. The impact is limited to applications using the specified vulnerable versions with the proxy handlers /me/* and /my-org/* and DPoP enabled. There are no known exploits in the wild at this time.
Mitigation Recommendations
Upgrade to Auth0 Next.js SDK version 4.18.0 or later, where this issue has been fixed. Since this is a library vulnerability, applying the official update is the recommended remediation. No other mitigations are indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-09T19:31:56.013Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69e2a136bdfbbecc59908353
Added to database: 4/17/2026, 9:08:06 PM
Last enriched: 4/25/2026, 2:55:46 AM
Last updated: 6/2/2026, 12:42:49 PM
Views: 69
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