# CVE-2026-118258: i18next-http-backend: Query-parameter injection through & and = in lng when loadPath/addPath puts {{lng}} in the query string

Source: https://junglewise.ai/threats/cve-2026-118258-i18next-http-backend-is-a-backend-layer-for-i18next-that-loads  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-28  
License: CC BY 4.0 with a link back

CVE-2026-118258 · Severity: low · CVSS 3.7 · Published 2026-10-28

i18next-http-backend is a backend layer for i18next that loads translation resources in Node.js, browsers, and Deno. Prior to 4.0.4, interpolateUrl inserts unencoded language and namespace values into loadPath or addPath templates without rejecting ampersand (&), equals (=), or semicolon (;) query separators. When a template places lng or ns in the query string and an attacker controls that value, the attacker can add or override parameters on browser or server-side translation requests, potentially exposing other namespaces or tenants or changing backend behavior through the application's network position and credentials. This vulnerability is the result of an incomplete fix for CVE-2026-41691. This issue is fixed in version 4.0.4.

Technologies: [i18next-http-backend (npm)](https://junglewise.ai/threats/technologies/i18next-http-backend). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-118258 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-118258 being exploited in the wild.

**How severe is CVE-2026-118258?** Low severity, with a CVSS score of 3.7, published 28 October 2026.

**Which products and versions are affected?** i18next-http-backend (npm) < 4.0.4, SEMVER:introduced=0,fixed=4.0.4.

**Is there a fix for CVE-2026-118258?** Yes. i18next-http-backend (npm): upgrade to 4.0.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2026-118258?** Check whether you run i18next-http-backend (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- i18next-http-backend (npm): upgrade to 4.0.4 or later

  ```sh
  npm install i18next-http-backend@4.0.4
  ```


## Affected products

- i18next-http-backend (npm) < 4.0.4, SEMVER:introduced=0,fixed=4.0.4

## Identifiers

- CVE-2026-118258
- GHSA-3cmx-xjww-583x

## Related threats

- [Duplicate Advisory: Namespace value starting with / forms a protocol-relative URL when loadPath/addPath places {{ns}} right after a / (bypass of the // check added for GHSA-xvq9-wjp8-hwqf)](https://junglewise.ai/threats/duplicate-advisory-namespace-value-starting-with-forms-a-protocol-0773444c)
- [i18next-http-backend: Namespace value starting with / forms a protocol-relative URL when loadPath/addPath places {{ns}} right after a / (bypass of the // check added for GHSA-xvq9-wjp8-hwqf)](https://junglewise.ai/threats/cve-2026-115730-i18next-http-backend-4-0-2-contains-an-incomplete-fix-in)
- [i18next-http-backend incomplete URL validation permits SSRF](https://junglewise.ai/threats/cve-2026-105800-i18next-http-backend-is-a-backend-layer-for-i18next-that-loads)
- [i18next-http-backend URL injection and path traversal](https://junglewise.ai/threats/cve-2026-41691-i18next-http-backend-url-injection-and-path-traversal)