amannn next-intl up to 4.9.0 WHATWG URL Parser redirect

CVSS Meta Temp Score
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CTI Interest Score
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3.4$0-$5k3.43

Summaryinfo

A vulnerability classified as problematic was found in amannn next-intl up to 4.9.0. The impacted element is an unknown function of the component WHATWG URL Parser. The manipulation results in redirect. This vulnerability is cataloged as CVE-2026-40299. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in amannn next-intl up to 4.9.0. It has been classified as problematic. Affected is an unknown function of the component WHATWG URL Parser. The manipulation with an unknown input leads to a redirect vulnerability. CWE is classifying the issue as CWE-601. A web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a Redirect. This simplifies phishing attacks. This is going to have an impact on integrity. CVE summarizes:

next-intl provides internationalization for Next.js. Applications using the `next-intl` middleware prior to version 4.9.1with `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. The problem has been patchedin `[email protected]`.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-40299 since 04/10/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. Successful exploitation requires user interaction by the victim. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1204.001 by the MITRE ATT&CK project.

Upgrading to version 4.9.1 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 1c80b668aa6d853f470319eec10a3f61e78a70e6 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 3.5
VulDB Meta Temp Score: 3.4

VulDB Base Score: 3.5
VulDB Temp Score: 3.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Redirect
CWE: CWE-601
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: next-intl 4.9.1
Patch: 1c80b668aa6d853f470319eec10a3f61e78a70e6

Timelineinfo

04/10/2026 CVE reserved
04/17/2026 +7 days Advisory disclosed
04/17/2026 +0 days VulDB entry created
04/17/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-8f24-v5vv-gm5j
Status: Confirmed

CVE: CVE-2026-40299 (🔒)
GCVE (CVE): GCVE-0-2026-40299
GCVE (VulDB): GCVE-100-358134

Entryinfo

Created: 04/17/2026 23:52
Changes: 04/17/2026 23:52 (71)
Complete: 🔍
Cache ID: 216::103

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