CVE-2026-40155

Name: CVE-2026-40155
Creator: NVD / NIST
Published: 2026-04-17T21:16:33.713+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.4/10EPSS 0.21%

Last modified Jun 17, 2026

CVE-2026-40155 is a medium-severity vulnerability rated 5.4/10 on the CVSS scale. 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. EPSS estimates a 0.21% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

5.4/10

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:L/A:N

EPSS Probability

0.21%

11.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Auth0	Nextjs-Auth0	>= 4.12.0, < 4.18.0

References

https://github.com/auth0/nextjs-auth0/commit/98c36dc306970c2230ea1a32efef431d29b99978Patch
https://github.com/auth0/nextjs-auth0/releases/tag/v4.18.0Product, Release Notes
https://github.com/auth0/nextjs-auth0/security/advisories/GHSA-xq8m-7c5p-c2r6Vendor Advisory

Timeline

Published: Apr 17, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-40155?

How severe is CVE-2026-40155?

CVE-2026-40155 has a CVSS score of 5.4/10 (MEDIUM severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.

How do I fix CVE-2026-40155?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-40155?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST