Next.js is a React framework for building full-stack web applications. To mitigate CVE-2025-29927, Next.js validated the x-middleware-subrequest-id which persisted across multiple incoming requests. However, this subrequest ID is sent to all requests, even if the destination is not the same host as the Next.js application. Initiating a fetch request to a third-party within Middleware will send the x-middleware-subrequest-id to that third party. This vulnerability is fixed in 12.3.6, 13.5.10, 14.2.26, and 15.2.4.
| Package (Ecosystem) | Introduced | Fixed | Limit |
|---|---|---|---|
| next(npm) | 12.3.5 | 12.3.6 | N/A |
| next(npm) | 13.5.9 | 13.5.10 | N/A |
| next(npm) | 14.2.25 | 14.2.26 | N/A |
| next(npm) | 15.2.3 | 15.2.4 | N/A |
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