A vulnerability in Next.js Middleware has been fixed in v14.2.32 and v15.4.7. The issue occurred when request headers were directly passed into NextResponse.next()
. In self-hosted applications, this could allow Server-Side Request Forgery (SSRF) if certain sensitive headers from the incoming request were reflected back into the response.
All users implementing custom middleware logic in self-hosted environments are strongly encouraged to upgrade and verify correct usage of the next()
function.
More details at Vercel Changelog
{ "severity": "MODERATE", "github_reviewed_at": "2025-08-29T21:33:09Z", "nvd_published_at": null, "cwe_ids": [ "CWE-918" ], "github_reviewed": true }