Vulnerability · Published May 8, 2026 · Assigned by GitHub_M
CVE-2026-41693i18next-fs-backend: Path traversal via unsanitised lng/ns allows arbitrary file read/overwrite
High 8.2
In plain English
A high-severity path traversal in i18next-fs-backend from i18next. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | i18next-fs-backend | 2.6.4 | GHSA-8847-338w-5hcj |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| i18next | i18next-fs-backend | < 2.6.4 |
Weakness: CWE-73, CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N