CVE-2026-41693

CVE-2026-41693 · i18next-fs-backend: Path traversal via unsanitised lng/ns allows arbitrary file read/overwrite

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i18next-fs-backend is a backend layer for i18next using in Node.js and for Deno to load translations from the filesystem. Prior to version 2.6.4, i18next-fs-backend substitutes the lng and ns options directly into the configured loadPath / addPath templates and then read / write the resulting file from disk. The interpolation is unencoded and unvalidated, so a crafted lng or ns value — containing .., a path separator, a control character, a prototype key, or simply an unexpectedly long string — allows an attacker who can influence either value to read or overwrite files outside the intended locale directory. When lng / ns are derived from untrusted input (request-scoped i18next instances behind an HTTP layer such as i18next-http-middleware, or any framework that lets the end user pick the language via query string, cookie, or header), a single request such as ?lng=../../../../etc/passwd causes the backend to attempt to read that path. This issue has been patched in version 2.6.4.

CVSS 8.2 · High · EPSS 0.3% · Fix available

Published

2026-05-08T15:38:50.525Z

Updated

2026-05-13T17:48:00.613Z

Stack: node

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