{"id":"CVE-2026-71321","aliases":["GHSA-9pgf-384g-p7mv"],"url":"https://o3.security/vulnerability/CVE-2026-71321","summary":"Nuxt: Unauthenticated CPU exhaustion parsing and hashing the Nuxt island endpoint body before hash validation","details":"### Impact\n\nThe internal island renderer endpoint (`/__nuxt_island/...`) decodes and hashes attacker-controlled request input before it validates the URL-resident hash. An unauthenticated `POST /__nuxt_island/<name>_<anything>.json` with a large JSON body (for example ~4.6 MB / 150k keys) is fully read, `destr`-parsed, and run through `ohash` before the request is rejected with a 400. Because Nitro runs on a single event loop, this both wastes CPU on the doomed request and delays every concurrent request. A low request rate is enough to degrade or stall the server. No valid hash and no authentication are required.\n\n### Patches\n\nFixed in `nuxt@4.5.1` and `nuxt@3.21.10`. The island handler now enforces a raw body-size cap (`413`) and a JSON nesting-depth cap (`400`) before parsing or hashing, so oversized or deeply nested input is rejected cheaply.\n\n### Workarounds\n\nPut a small request-body limit in front of `/__nuxt_island/` at your reverse proxy / edge (islands legitimately send only a compact props payload), or disable server components if unused.","published":"2026-08-05T21:42:48.161Z","modified":"2026-10-28T02:31:07.913565234Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":{"score":0.00422,"percentile":0.36015,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"nuxt","fixedVersion":"4.5.1"},{"ecosystem":"npm","name":"nuxt","fixedVersion":"3.21.10"}],"fix":{"url":"https://github.com/nuxt/nuxt/commit/4e35ae9babd94be53246e31200232d48438bb34e","label":"nuxt/nuxt@4e35ae9"},"references":[{"type":"WEB","url":"https://github.com/nuxt/nuxt/releases/tag/v3.21.10"},{"type":"WEB","url":"https://github.com/nuxt/nuxt/releases/tag/v4.5.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71321.json"},{"type":"ADVISORY","url":"https://github.com/nuxt/nuxt/security/advisories/GHSA-9pgf-384g-p7mv"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-71321"},{"type":"FIX","url":"https://github.com/nuxt/nuxt/commit/4e35ae9babd94be53246e31200232d48438bb34e"},{"type":"FIX","url":"https://github.com/nuxt/nuxt/commit/668cdfdfda41849ed11c1ee5e2067a11fc103b22"},{"type":"PACKAGE","url":"https://github.com/nuxt/nuxt"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:31:07.913565234Z"}}