GHSA-8F24-V5VV-GM5J
Vulnerability from github – Published: 2026-04-10 21:03 – Updated: 2026-04-14 21:54
VLAI?
Summary
next-intl has an open redirect vulnerability
Details
Impact
Applications 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.
Patches
The problem has been patched, please update to next-intl@4.9.1.
Credits
Many thanks to Joni Liljeblad from Oura for responsibly disclosing the vulnerability and for suggesting the fix.
Severity ?
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "next-intl"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.9.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-40299"
],
"database_specific": {
"cwe_ids": [
"CWE-601"
],
"github_reviewed": true,
"github_reviewed_at": "2026-04-10T21:03:55Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "### Impact\n\nApplications using the `next-intl` middleware with `localePrefix: \u0027as-needed\u0027` 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.",
"id": "GHSA-8f24-v5vv-gm5j",
"modified": "2026-04-14T21:54:59Z",
"published": "2026-04-10T21:03:55Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/amannn/next-intl/security/advisories/GHSA-8f24-v5vv-gm5j"
},
{
"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"
}
],
"schema_version": "1.4.0",
"severity": [
{
"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",
"type": "CVSS_V4"
}
],
"summary": "next-intl has an open redirect vulnerability"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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