CVE-2026-48713

CVE-2026-48713 affects i18next-fs-backend prior to 2.6.6. The issue arises when crafted missing-key strings are persisted via missingKeyHandler, where Backend.writeFile() splits keys on keySeparator and the path walker could reach Object.prototype (e.g., a key like "proto .polluted"), allowing pr...

CVE-2026-48713 i18next-fs-backend: Prototype pollution via crafted missing-key string

Versions prior to 2.6.6 are vulnerable to prototype pollution via crafted missing-key strings when used to persist missing translation keys e.g. via i18next-http-middleware's missingKeyHandler exposed to untrusted input. Backend.writeFile splits each queued missing-key string on the configured...

External Control of File Name or Path

Overview i18next-fs-backend is an i18next-fs-backend is a backend layer for i18next using in Node.js and for Deno to load translations from the filesystem. Affected versions of this package are vulnerable to External Control of File Name or Path that leads to raw interpolation of lng and ns value...