CVE-2026-40155
Auth0 Next.js SDK has Improper Proxy Cache Lookup
Description
### Description In affected versions of the Next.js SDK, simultaneous requests that trigger a nonce retry may cause the proxy cache fetcher to perform improper lookups for the token request results. ### Which Projects are Affected? Users are affected if they meet all of the following preconditions: - Applications using the auth0/nextjs-auth0 SDK, versions 4.12.0 to 4.17.0, and - Applications using the proxy handler /me/* and /my-org/* with DPoP enabled. ### Affected product and versions Auth0/nextjs-auth0 v4.12.0 to 4.17.0 ### Resolution Upgrade Auth0/nextjs-auth0 version to v4.18.0 or greater ### Acknowledgements Okta would like to thank Reynaldo Immanuel for their discovery and responsible disclosure.
How to fix CVE-2026-40155
To remediate CVE-2026-40155, upgrade the affected package to a fixed version below.
- —upgrade to 4.18.0 or later
Is CVE-2026-40155 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- >= 4.12.0, < 4.18.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.4 | CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:L/A:N |