locize i18next--backend up to 9.0.1 lib/index.js interpolate path traversal

Summaryinfo

A vulnerability was found in locize i18next--backend up to 9.0.1. It has been rated as critical. This vulnerability affects the function interpolate in the library lib/index.js. This manipulation causes path traversal. The identification of this vulnerability is CVE-2026-41885. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in locize i18next--backend up to 9.0.1 and classified as critical. Affected by this vulnerability is the function interpolate in the library lib/index.js. The manipulation with an unknown input leads to a path traversal vulnerability. The CWE definition for the vulnerability is CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

i18next-locize-backend is a simple i18next backend for locize.com which can be used in Node.js, in the browser and for Deno. Prior to version 9.0.2, i18next-locize-backend interpolates lng, ns, projectId, and version directly into the configured loadPath / privatePath / addPath / updatePath / getLanguagesPath URL templates with no path-component validation and no encoding. When an application exposes any of these values to user-controlled input (?lng= / ?ns= query parameters via i18next-browser-languagedetector, cookies, request headers, or a URL-derived projectId), a crafted value can change the structure of the outgoing request URL. Affected call sites in lib/index.js (pre-patch): the interpolate() helper is used at the five URL-build sites — _readAny/read (line 415 for private, 426 for public), getLanguages (lines 271 and 296), and writePage (lines 616 and 622) for the missing-key and update POST paths. The helper interpolate in lib/utils.js substitutes raw values with no encoding. This issue has been patched in version 9.0.2.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-41885 since 04/22/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1006 according to MITRE ATT&CK.

Upgrading to version 9.0.2 eliminates this vulnerability.

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Productinfo

Vendor

• locize

Name

• i18next--backend

Version

• 9.0.0
• 9.0.1

CPE 2.3info

• 🔒
• 🔒

CPE 2.2info

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• 🔒

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