{"id":"CVE-2022-21721","aliases":["GHSA-wr66-vrwm-5g5x"],"url":"https://o3.security/vulnerability/CVE-2022-21721","summary":"DOS Vulnerability in next.js","details":"### 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 >= 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","published":"2022-01-28T22:00:17Z","modified":"2026-08-12T03:51:17.630950415Z","cvss":{"score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":{"score":0.02153,"percentile":0.81241,"asOf":"2026-09-16"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"next","fixedVersion":"12.0.9"}],"fix":{"url":"https://github.com/vercel/next.js/pull/33503","label":"vercel/next.js#33503"},"references":[{"type":"WEB","url":"https://github.com/vercel/next.js/releases/tag/v12.0.9"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/21xxx/CVE-2022-21721.json"},{"type":"ADVISORY","url":"https://github.com/vercel/next.js/security/advisories/GHSA-wr66-vrwm-5g5x"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-21721"},{"type":"FIX","url":"https://github.com/vercel/next.js/pull/33503"},{"type":"PACKAGE","url":"https://github.com/vercel/next.js"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:17.630950415Z"}}