{"id":"GHSA-8f24-v5vv-gm5j","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.","aliases":["CVE-2026-40299"],"modified":"2026-05-05T16:04:42.763137Z","published":"2026-04-10T21:03:55Z","database_specific":{"github_reviewed_at":"2026-04-10T21:03:55Z","nvd_published_at":"2026-04-17T21:16:34Z","cwe_ids":["CWE-601"],"severity":"MODERATE","github_reviewed":true},"references":[{"type":"WEB","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":"WEB","url":"https://github.com/amannn/next-intl/pull/2304"},{"type":"WEB","url":"https://github.com/amannn/next-intl/commit/1c80b668aa6d853f470319eec10a3f61e78a70e6"},{"type":"PACKAGE","url":"https://github.com/amannn/next-intl"},{"type":"WEB","url":"https://github.com/amannn/next-intl/releases/tag/v4.9.1"}],"affected":[{"package":{"name":"next-intl","ecosystem":"npm","purl":"pkg:npm/next-intl"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.9.1"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-8f24-v5vv-gm5j/GHSA-8f24-v5vv-gm5j.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"}]}