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.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-8847-338w-5hcj i18next-fs-backend: Path traversal via unsanitised lng/ns allows arbitrary file read/overwrite
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 13 May 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Sun, 10 May 2026 21:45:00 +0000

Type Values Removed Values Added
First Time appeared I18next
I18next i18next-fs-backend
Vendors & Products I18next
I18next i18next-fs-backend

Fri, 08 May 2026 16:00:00 +0000

Type Values Removed Values Added
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.
Title i18next-fs-backend: Path traversal via unsanitised lng/ns allows arbitrary file read/overwrite
Weaknesses CWE-22
CWE-73
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-13T17:48:00.613Z

Reserved: 2026-04-22T03:53:24.407Z

Link: CVE-2026-41693

cve-icon Vulnrichment

Updated: 2026-05-13T17:47:54.499Z

cve-icon NVD

Status : Deferred

Published: 2026-05-08T16:16:11.613

Modified: 2026-05-12T15:29:40.830

Link: CVE-2026-41693

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-10T21:25:08Z

Weaknesses