# CVE-2026-105800: i18next-http-backend incomplete URL validation permits SSRF

> Attackers can trigger SSRF or URL injection in i18next-http-backend by manipulating language or namespace values in custom load paths.

- **Severity:** Low 3.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Oct 2026
- **Updated:** 6 Oct 2026
- **Also known as:** CLSA-2026-1792233117, CLSA-2026-1792233236, DEBIAN-CVE-2026-105800, GHSA-xvq9-wjp8-hwqf, UBUNTU-CVE-2026-105800

## What is CVE-2026-105800?

CVE-2026-105800 is a low-severity server-side request forgery vulnerability in i18next-http-backend, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

i18next-http-backend is a backend layer for i18next that loads translation resources in Node.js, browsers, and Deno. Prior to 4.0.2, attacker-controlled language or namespace values interpolated into a custom loadPath or addPath that begins directly with {{lng}} or {{ns}} can make colon-based input become an absolute URL or, in browsers, make a double-slash namespace become a protocol-relative URL. The resulting request can leave the intended origin and cause URL injection or server-side request forgery. The default /locales/{{lng}}/{{ns}}.json template and templates with a leading path or origin are not affected because the placeholder does not occupy the URL's structural beginning. This issue is fixed in version 4.0.2.

Weakness: CWE-918 (Server-Side Request Forgery), CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component)

## Which versions are affected by CVE-2026-105800?

2 open source packages ship an affected version, including i18next-http-backend.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `i18next-http-backend` | npm | All versions | 4.0.2 |
| `i18next-http-backend` | npm | All versions | 4.0.2 |

## How do I fix CVE-2026-105800?

Upgrade i18next-http-backend to 4.0.2 or later.

## Is CVE-2026-105800 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-105800 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-105800 and fix it if it is affected.

What it is: CVE-2026-105800 is a low-severity server-side request forgery vulnerability in i18next-http-backend, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-105800 exists.

Affected packages and fixed versions:
- i18next-http-backend (npm): affected all versions; fixed in 4.0.2
- i18next-http-backend (npm): affected all versions; fixed in 4.0.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-105800/ (Markdown: https://insights.sbomify.com/CVE-2026-105800/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-105800
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-105800
- OSV: https://osv.dev/vulnerability/CVE-2026-105800

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-105800/
Summaries are generated and may contain mistakes; the official description above is the record.