i18next-http-backend is a backend layer for i18next that loads translation resources in Node.js, browsers, and Deno. Prior to 4.0.2, attacker-controlled language or namespace values interpolated into a custom loadPath or addPath that begins directly with {{lng}} or {{ns}} can make colon-based input become an absolute URL or, in browsers, make a double-slash namespace become a protocol-relative URL. The resulting request can leave the intended origin and cause URL injection or server-side request forgery. The default /locales/{{lng}}/{{ns}}.json template and templates with a leading path or origin are not affected because the placeholder does not occupy the URL's structural beginning. This issue is fixed in version 4.0.2.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-74",
"CWE-918"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/105xxx/CVE-2026-105800.json"
}