{"id":"CVE-2026-40299","aliases":["GHSA-8f24-v5vv-gm5j"],"url":"https://o3.security/vulnerability/CVE-2026-40299","summary":"next-intl has an open redirect vulnerability","details":"### Impact\n\nApplications using the `next-intl` middleware with `localePrefix: 'as-needed'` could construct URLs where path handling and the WHATWG URL parser resolved a relative redirect target to another host (e.g. scheme-relative `//` or control characters stripped by the URL parser), so the middleware could redirect the browser off-site while the user still started from a trusted app URL.\n\n### Patches\n\nThe problem has been patched, please update to [`next-intl@4.9.1`](https://github.com/amannn/next-intl/releases/tag/v4.9.1).\n\n### Credits\n\nMany thanks to [Joni Liljeblad](https://github.com/joniumGit) from [Oura](https://ouraring.com) for responsibly disclosing the vulnerability and for suggesting the fix.","published":"2026-04-17T20:49:05.642Z","modified":"2026-10-28T02:31:02.818394094Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"next-intl","fixedVersion":"4.9.1"}],"fix":{"url":"https://github.com/amannn/next-intl/commit/1c80b668aa6d853f470319eec10a3f61e78a70e6","label":"amannn/next-intl@1c80b66"},"references":[{"type":"WEB","url":"https://github.com/amannn/next-intl/releases/tag/v4.9.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40299.json"},{"type":"ADVISORY","url":"https://github.com/amannn/next-intl/security/advisories/GHSA-8f24-v5vv-gm5j"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40299"},{"type":"FIX","url":"https://github.com/amannn/next-intl/commit/1c80b668aa6d853f470319eec10a3f61e78a70e6"},{"type":"FIX","url":"https://github.com/amannn/next-intl/pull/2304"},{"type":"PACKAGE","url":"https://github.com/amannn/next-intl"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:31:02.818394094Z"}}