ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2026-40299

next-intl provides internationalization for Next.js.

Published Apr 17, 2026 · catalog updated Jun 17, 2026 · next-intl provides internationalization for

Check if you run it

No confirmed exploitation is on record for CVE-2026-40299. EPSS is 0.54%. Act only if a listed version of next-intl provides internationalization for is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (next-intl provides internationalization for).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.9
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.54%
Remediation
Advisory link
Affected products
See sources for product scope

next-intl provides internationalization for Next.js. Applications using the middleware prior to version 4.9.1with 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 .

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-40299

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-40299. EPSS is 0.54%. Act only if a listed version of next-intl provides internationalization for is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-601: URL Redirection to Untrusted Site (Open Redirect). EPSS 0.54%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 17, 2026 · NIST NVD

    Detected

    next-intl provides internationalization for Next.js. Applications using the middleware prior to version 4.9.1with 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 trus

  2. Jun 17, 2026 · NIST NVD

    Updated

    next-intl provides internationalization for Next.js. Applications using the middleware prior to version 4.9.1with 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 trus

Sources

  • CVE.orgVulnerability recordCVE-2026-40299

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-40299

    30-day exploitation probability 0.5%

    first.org
  • NIST NVDVulnerability recordCVE-2026-40299

    next-intl provides internationalization for Next.js. Applications using the middleware prior to version 4.9.1with could construct URLs where path handling and the WHATWG URL parser resolved a relative redirect target to another host (e.g. s

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.