{"id":"CVE-2022-21721","aliases":["EUVD-2022-0727","GHSA-wr66-vrwm-5g5x"],"status":"published","title":"DOS Vulnerability in next.js","description":"Next.js is a React framework. Starting with version 12.0.0 and prior to version 12.0.9, vulnerable code could allow a bad actor to trigger a denial of service attack for anyone using i18n functionality. In order to be affected by this CVE, one must use next start or a custom server and the built-in i18n support. Deployments on Vercel, along with similar environments where invalid requests are filtered before reaching Next.js, are not affected. A patch has been released, `next@12.0.9`, that mitigates this issue. As a workaround, one may ensure `/${locale}/_next/` is blocked from reaching the Next.js instance until it becomes feasible to upgrade.","severity":{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.02153,"percentile":0.82306,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-20","CWE-400"],"published":"2022-01-28T22:00:17Z","modified":"2026-10-28T02:30:27Z","fixes":[{"ecosystem":"npm","package":"next","fixed_in":["12.0.9"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"next","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"12.0.0"},{"fixed":"12.0.9"}]}]},{"source":"osv","ecosystem":"npm","package":"next","ranges":[{"type":"SEMVER","events":[{"introduced":"12.0.0"},{"fixed":"12.0.9"}]}]}],"products":[{"vendor":"vercel","product":"next.js"}],"references":[{"url":"https://github.com/vercel/next.js/security/advisories/GHSA-wr66-vrwm-5g5x","tags":["x_refsource_CONFIRM","x_transferred","Third Party Advisory","advisory","web"]},{"url":"https://github.com/vercel/next.js/pull/33503","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","web"]},{"url":"https://github.com/vercel/next.js/releases/tag/v12.0.9","tags":["x_refsource_MISC","x_transferred","Release Notes","Third Party Advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2022-21721","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-wr66-vrwm-5g5x"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/21xxx/CVE-2022-21721.json","tags":["advisory"]},{"url":"https://github.com/vercel/next.js","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2022-21721","title":"DOS Vulnerability in next.js","description":"Next.js is a React framework. Starting with version 12.0.0 and prior to version 12.0.9, vulnerable code could allow a bad actor to trigger a denial of service attack for anyone using i18n functionality. In order to be affected by this CVE, one must use next start or a custom server and the built-in i18n support. Deployments on Vercel, along with similar environments where invalid requests are filtered before reaching Next.js, are not affected. A patch has been released, `next@12.0.9`, that mitigates this issue. As a workaround, one may ensure `/${locale}/_next/` is blocked from reaching the Next.js instance until it becomes feasible to upgrade.","status":"published","published":"2022-01-28T22:00:17Z","modified":"2025-05-05T16:33:30.538Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"updated_at":"2026-11-02T14:34:29.057251Z"}],"euvd":[{"id":"EUVD-2022-0727","description":"Next.js is a React framework. Starting with version 12.0.0 and prior to version 12.0.9, vulnerable code could allow a bad actor to trigger a denial of service attack for anyone using i18n functionality. In order to be affected by this CVE, one must use next start or a custom server and the built-in i18n support. Deployments on Vercel, along with similar environments where invalid requests are filtered before reaching Next.js, are not affected. A patch has been released, `next@12.0.9`, that mitigates this issue. As a workaround, one may ensure `/${locale}/_next/` is blocked from reaching the Next.js instance until it becomes feasible to upgrade.","status":"published","published":"2022-01-28T22:00:17Z","modified":"2025-05-05T16:33:30Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T20:32:56.549702Z"}],"ghsa":[{"id":"GHSA-wr66-vrwm-5g5x","title":"Denial of Service Vulnerability in next.js","description":"### Impact\n\nVulnerable code could allow a bad actor to trigger a denial of service attack for anyone running a Next.js app at version \u003e= 12.0.0, and using i18n functionality.\n\n- **Affected:** All of the following must be true to be affected by this CVE\n  - Next.js versions above v12.0.0\n  - Using next start or a custom server\n  - Using the built-in i18n support\n- **Not affected:**\n  - Deployments on Vercel (vercel.com) are not affected along with similar environments where invalid requests are filtered before reaching Next.js.\n\n### Patches\n\nA patch has been released, `next@12.0.9`, that mitigates this issue. We recommend all affected users upgrade as soon as possible.\n\n### Workarounds\n\nWe recommend upgrading whether you can reproduce or not although you can ensure `/${locale}/_next/` is blocked from reaching the Next.js instance until you upgrade.\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n* Open an issue in [next](https://github.com/vercel/next.js)\n* Email us at [security@vercel.com](mailto:security@vercel.com)\n","status":"published","published":"2022-01-28T23:09:22Z","modified":"2023-12-20T16:39:40Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-20","CWE-400"],"updated_at":"2026-11-02T14:37:27.414424Z"}],"nvd":[{"id":"CVE-2022-21721","description":"Next.js is a React framework. Starting with version 12.0.0 and prior to version 12.0.9, vulnerable code could allow a bad actor to trigger a denial of service attack for anyone using i18n functionality. In order to be affected by this CVE, one must use next start or a custom server and the built-in i18n support. Deployments on Vercel, along with similar environments where invalid requests are filtered before reaching Next.js, are not affected. A patch has been released, `next@12.0.9`, that mitigates this issue. As a workaround, one may ensure `/${locale}/_next/` is blocked from reaching the Next.js instance until it becomes feasible to upgrade.","status":"published","published":"2022-01-28T22:15:16.36Z","modified":"2026-06-17T04:26:51.3Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"},{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:N/I:N/A:P","level":"medium","assessor":"primary"}],"updated_at":"2026-11-02T14:07:11.52734Z"}],"osv":[{"id":"CVE-2022-21721","title":"DOS Vulnerability in next.js","description":"Next.js is a React framework. Starting with version 12.0.0 and prior to version 12.0.9, vulnerable code could allow a bad actor to trigger a denial of service attack for anyone using i18n functionality. In order to be affected by this CVE, one must use next start or a custom server and the built-in i18n support. Deployments on Vercel, along with similar environments where invalid requests are filtered before reaching Next.js, are not affected. A patch has been released, `next@12.0.9`, that mitigates this issue. As a workaround, one may ensure `/${locale}/_next/` is blocked from reaching the Next.js instance until it becomes feasible to upgrade.","status":"published","published":"2022-01-28T22:00:17Z","modified":"2026-10-28T02:30:27.833531306Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:44:23.655778Z"},{"id":"GHSA-wr66-vrwm-5g5x","title":"Denial of Service Vulnerability in next.js","description":"### Impact\n\nVulnerable code could allow a bad actor to trigger a denial of service attack for anyone running a Next.js app at version \u003e= 12.0.0, and using i18n functionality.\n\n- **Affected:** All of the following must be true to be affected by this CVE\n  - Next.js versions above v12.0.0\n  - Using next start or a custom server\n  - Using the built-in i18n support\n- **Not affected:**\n  - Deployments on Vercel (vercel.com) are not affected along with similar environments where invalid requests are filtered before reaching Next.js.\n\n### Patches\n\nA patch has been released, `next@12.0.9`, that mitigates this issue. We recommend all affected users upgrade as soon as possible.\n\n### Workarounds\n\nWe recommend upgrading whether you can reproduce or not although you can ensure `/${locale}/_next/` is blocked from reaching the Next.js instance until you upgrade.\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n* Open an issue in [next](https://github.com/vercel/next.js)\n* Email us at [security@vercel.com](mailto:security@vercel.com)\n","status":"published","published":"2022-01-28T23:09:22Z","modified":"2026-09-10T03:49:11.471300399Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-20","CWE-400"],"updated_at":"2026-11-02T15:46:59.131095Z"}]}}