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Next.js dropped a CVSS 9.1 authentication bypass vulnerability (CVE-2025-29927) over the weekend. This flaw is trivially exploitable by sending the header `x-middleware-subrequest: true` and causes the request to skip all middleware processing, including any authentication steps.

Shodan reports over 300,000 services with the `X-Powered-By: Next.js` header alone.

You can find links to the advisory and queries for runZero at: https://www.runzero.com/blog/next-js/