{"id":"CVE-2025-30218","summary":"Next.js may leak x-middleware-subrequest-id to external hosts","details":"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.","aliases":["GHSA-223j-4rm8-mrmf"],"modified":"2026-08-12T03:30:47.453602618Z","published":"2025-04-02T21:23:14.660Z","database_specific":{"cwe_ids":["CWE-200"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/30xxx/CVE-2025-30218.json","cna_assigner":"GitHub_M"},"references":[{"type":"WEB","url":"https://vercel.com/changelog/cve-2025-30218-5DREmEH765PoeAsrNNQj3O"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/30xxx/CVE-2025-30218.json"},{"type":"ADVISORY","url":"https://github.com/vercel/next.js/security/advisories/GHSA-223j-4rm8-mrmf"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-30218"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/vercel/next.js","events":[{"introduced":"6687ab55a362f1fe8cb15a76640cc87ff90d15f2"},{"last_affected":"535e26d3c69de49df8bd17618a424cbe65ec897b"}],"database_specific":{"cpe":["cpe:2.3:a:vercel:next.js:12.3.5:*:*:*:*:node.js:*:*","cpe:2.3:a:vercel:next.js:13.5.9:*:*:*:*:node.js:*:*","cpe:2.3:a:vercel:next.js:14.2.25:*:*:*:*:node.js:*:*","cpe:2.3:a:vercel:next.js:15.2.3:*:*:*:*:node.js:*:*"],"extracted_events":[{"introduced":"= 12.3.5"},{"last_affected":"= 12.3.5"},{"introduced":"= 13.5.9"},{"last_affected":"= 13.5.9"},{"introduced":"= 14.2.25"},{"last_affected":"= 14.2.25"},{"introduced":"= 15.2.3"},{"last_affected":"= 15.2.3"},{"introduced":"12.3.5"},{"last_affected":"12.3.5"},{"introduced":"13.5.9"},{"last_affected":"13.5.9"},{"introduced":"14.2.25"},{"last_affected":"14.2.25"},{"introduced":"15.2.3"},{"last_affected":"15.2.3"}],"source":["AFFECTED_FIELD","CPE_STRING"]}}],"versions":["12.3.5","13.5.9","14.2.25","15.2.3","= 12.3.5","= 13.5.9","= 14.2.25","= 15.2.3"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-30218.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U"}]}