{"id":"CVE-2025-30218","aliases":["EUVD-2025-9629","GHSA-223j-4rm8-mrmf"],"status":"published","title":"Next.js may leak x-middleware-subrequest-id to external hosts","description":"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.","severity":{"version":"4.0","score":1.7,"vector":"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","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00431,"percentile":0.37813,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-200"],"published":"2025-04-02T21:23:14Z","modified":"2026-10-28T02:30:41Z","fixes":[{"ecosystem":"npm","package":"next","fixed_in":["12.3.6","13.5.10","14.2.26","15.2.4"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"next","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"12.3.5"},{"last_affected":"12.3.5"},{"fixed":"12.3.6"}]}],"versions":["12.3.5"]},{"source":"ghsa","ecosystem":"npm","package":"next","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"13.5.9"},{"last_affected":"13.5.9"},{"fixed":"13.5.10"}]}],"versions":["13.5.9"]},{"source":"ghsa","ecosystem":"npm","package":"next","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"14.2.25"},{"last_affected":"14.2.25"},{"fixed":"14.2.26"}]}],"versions":["14.2.25"]},{"source":"ghsa","ecosystem":"npm","package":"next","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"15.2.3"},{"last_affected":"15.2.3"},{"fixed":"15.2.4"}]}],"versions":["15.2.3"]},{"source":"osv","ecosystem":"npm","package":"next","ranges":[{"type":"SEMVER","events":[{"introduced":"12.3.5"},{"fixed":"12.3.6"}]}],"versions":["12.3.5"]},{"source":"osv","ecosystem":"npm","package":"next","ranges":[{"type":"SEMVER","events":[{"introduced":"13.5.9"},{"fixed":"13.5.10"}]}],"versions":["13.5.9"]},{"source":"osv","ecosystem":"npm","package":"next","ranges":[{"type":"SEMVER","events":[{"introduced":"14.2.25"},{"fixed":"14.2.26"}]}],"versions":["14.2.25"]},{"source":"osv","ecosystem":"npm","package":"next","ranges":[{"type":"SEMVER","events":[{"introduced":"15.2.3"},{"fixed":"15.2.4"}]}],"versions":["15.2.3"]}],"products":[{"vendor":"vercel","product":"next.js"}],"references":[{"url":"https://github.com/vercel/next.js/security/advisories/GHSA-223j-4rm8-mrmf","tags":["x_refsource_CONFIRM","Vendor Advisory","advisory","web"]},{"url":"https://vercel.com/changelog/cve-2025-30218-5DREmEH765PoeAsrNNQj3O","tags":["x_refsource_MISC","Vendor Advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-30218","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-223j-4rm8-mrmf"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/30xxx/CVE-2025-30218.json","tags":["advisory"]},{"url":"https://github.com/vercel/next.js","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2025-30218","title":"Next.js may leak x-middleware-subrequest-id to external hosts","description":"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.","status":"published","published":"2025-04-02T21:23:14.66Z","modified":"2025-10-13T15:37:02.31Z","cvss":[{"version":"4.0","score":1.7,"vector":"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","level":"low","assessor":"cna"}],"cwes":["CWE-200"],"updated_at":"2026-11-02T14:32:35.418416Z"}],"euvd":[{"id":"EUVD-2025-9629","description":"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.","status":"published","published":"2025-04-02T21:23:14Z","modified":"2025-10-13T15:37:02Z","cvss":[{"version":"4.0","score":1.7,"vector":"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","level":"low"}],"updated_at":"2026-11-02T20:31:33.532032Z"}],"ghsa":[{"id":"GHSA-223j-4rm8-mrmf","title":"Next.js may leak x-middleware-subrequest-id to external hosts","description":"## Summary\nIn the process of remediating [CVE-2025-29927](https://github.com/advisories/GHSA-f82v-jwr5-mffw), we looked at other possible exploits of Middleware. We independently verified this low severity vulnerability in parallel with two reports from independent researchers.\n\nLearn more [here](https://vercel.com/changelog/cve-2025-30218-5DREmEH765PoeAsrNNQj3O).\n\n## Credit\n\nThank you to Jinseo Kim [kjsman](https://hackerone.com/kjsman?type=user) and [RyotaK](https://hackerone.com/ryotak?type=user) (GMO Flatt Security Inc.) with [takumi-san.ai](https://takumi-san.ai) for the responsible disclosure. These researchers were awarded as part of our bug bounty program.","status":"published","published":"2025-04-02T22:35:37Z","modified":"2025-10-13T15:35:51Z","cvss":[{"version":"4.0","score":1.7,"vector":"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","level":"low"}],"cwes":["CWE-200"],"updated_at":"2026-11-02T14:39:00.807341Z"}],"nvd":[{"id":"CVE-2025-30218","description":"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.","status":"published","published":"2025-04-02T22:15:19.94Z","modified":"2026-06-17T09:08:22.653Z","cvss":[{"version":"4.0","score":1.7,"vector":"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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"low","assessor":"secondary"},{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-200"],"updated_at":"2026-11-02T14:10:58.094557Z"}],"osv":[{"id":"CVE-2025-30218","title":"Next.js may leak x-middleware-subrequest-id to external hosts","description":"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.","status":"published","published":"2025-04-02T21:23:14.66Z","modified":"2026-10-28T02:30:41.001288873Z","cvss":[{"version":"4.0","score":1.7,"vector":"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","level":"low"}],"cwes":["CWE-200"],"updated_at":"2026-11-02T15:44:47.708311Z"},{"id":"GHSA-223j-4rm8-mrmf","title":"Next.js may leak x-middleware-subrequest-id to external hosts","description":"## Summary\nIn the process of remediating [CVE-2025-29927](https://github.com/advisories/GHSA-f82v-jwr5-mffw), we looked at other possible exploits of Middleware. We independently verified this low severity vulnerability in parallel with two reports from independent researchers.\n\nLearn more [here](https://vercel.com/changelog/cve-2025-30218-5DREmEH765PoeAsrNNQj3O).\n\n## Credit\n\nThank you to Jinseo Kim [kjsman](https://hackerone.com/kjsman?type=user) and [RyotaK](https://hackerone.com/ryotak?type=user) (GMO Flatt Security Inc.) with [takumi-san.ai](https://takumi-san.ai) for the responsible disclosure. These researchers were awarded as part of our bug bounty program.","status":"published","published":"2025-04-02T22:35:37Z","modified":"2025-10-13T15:35:50Z","cvss":[{"version":"4.0","score":1.7,"vector":"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","level":"low"}],"cwes":["CWE-200"],"updated_at":"2026-11-02T15:46:33.520522Z"}]}}