How severe is CVE-2026-40155?

CVE-2026-40155 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity low, and availability none.

Is CVE-2026-40155 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-40155?

CVE-2026-40155 affects Auth0 Nextjs-auth0. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-40155?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-40155 have an EU (EUVD) identifier?

Yes. CVE-2026-40155 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23537.

When was CVE-2026-40155 published?

CVE-2026-40155 was published on 2026-04-17 and last updated on 2026-06-17.

CVE-2026-40155

CVE-2026-40155 is a medium-severity vulnerability in Auth0 Nextjs-auth0 with a CVSS 3.x base score of 5.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-362.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
EPSS exploit prediction: 0% (12th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-23537
Weakness: CWE-362
Affected product: Auth0 Nextjs-auth0
Published: 2026-04-17
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-40155?: 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.
How severe is CVE-2026-40155?: CVE-2026-40155 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity low, and availability none.
Is CVE-2026-40155 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-40155?: CVE-2026-40155 affects Auth0 Nextjs-auth0. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-40155?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-40155 have an EU (EUVD) identifier?: Yes. CVE-2026-40155 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23537.
When was CVE-2026-40155 published?: CVE-2026-40155 was published on 2026-04-17 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:auth0:nextjs-auth0:*:*:*:*:*:node.js:*:*

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