{"cve":{"cve_id":"CVE-2026-40299","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":0.00339,"epss_percentile":0.25612,"epss_as_of":"2026-06-23","description":"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 `next-intl@4.9.1`.","published_at":"2026-04-17T20:49:05.642000Z","last_modified_at":null,"cvss_v3_score":null,"cvss_v3_vector":null,"cvss_v3_severity":null,"cvss_v4_score":6.9,"cvss_v4_vector":"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","cvss_v4_severity":"MEDIUM","ssvc_decision":null,"ssvc_exploitation":null,"ssvc_automatable":null,"ssvc_technical_impact":null,"cwes":["CWE-601"],"nvd_references":["https://github.com/amannn/next-intl/security/advisories/GHSA-8f24-v5vv-gm5j","https://github.com/amannn/next-intl/pull/2304","https://github.com/amannn/next-intl/commit/1c80b668aa6d853f470319eec10a3f61e78a70e6","https://github.com/amannn/next-intl/releases/tag/v4.9.1"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-24T00:09:39.878444Z","updated_at":"2026-06-28T23:30:11.113779Z"},"effective_severity":"MEDIUM","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":null,"metrics":[]},"cvss_v4_decoded":{"version":"4.0","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"AT","name":"Attack Requirements","value":"N","value_label":"None"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"VC","name":"Confidentiality (Vulnerable System)","value":"N","value_label":"None"},{"metric":"VI","name":"Integrity (Vulnerable System)","value":"L","value_label":"Low"},{"metric":"VA","name":"Availability (Vulnerable System)","value":"N","value_label":"None"},{"metric":"SC","name":"Confidentiality (Subsequent System)","value":"N","value_label":"None"},{"metric":"SI","name":"Integrity (Subsequent System)","value":"N","value_label":"None"},{"metric":"SA","name":"Availability (Subsequent System)","value":"N","value_label":"None"}]},"affected":[{"vendor_slug":"amannn","vendor_name":"amannn","product_slug":"next-intl","product_name":"next-intl","version_start":"< 4.9.1","version_start_inclusive":true,"version_end":"< 4.9.1","version_end_inclusive":true,"cpe23_uri":"cve5:amannn:next-intl:< 4.9.1:< 4.9.1"}],"exploit_refs":[],"news":[],"references":[{"url":"https://github.com/amannn/next-intl/security/advisories/GHSA-8f24-v5vv-gm5j","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://github.com/amannn/next-intl/pull/2304","source_type":"PATCH","tags":["patch"]},{"url":"https://github.com/amannn/next-intl/commit/1c80b668aa6d853f470319eec10a3f61e78a70e6","source_type":"PATCH","tags":["patch"]},{"url":"https://github.com/amannn/next-intl/releases/tag/v4.9.1","source_type":"PATCH","tags":["patch"]}],"timeline":[{"type":"published","at":"2026-04-17T20:49:05.642000Z","label":"CVE published","source":null},{"type":"cvss_changed","at":"2026-06-28T17:53:54.482027Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:53:54.482027Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:53:54.482027Z","label":"CVSS score revised","source":"cvelistv5"}]}