CVE-2026-105800

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.

• github.comhttps://github.com/i18next/i18next-http-backend/commit/07e028862b25d0b9251bf3cafb92be2d35285f85
• github.comhttps://github.com/i18next/i18next-http-backend/releases/tag/v4.0.2
• github.comhttps://github.com/i18next/i18next-http-backend/security/advisories/GHSA-xvq9-wjp8-hwqf
• github.comhttps://github.com/i18next/i18next-http-backend/security/advisories/GHSA-xvq9-wjp8-hwqf