CVE-2026-42353 Path traversal / SSRF in i18next-http-middleware via user-controlled language and namespace parameters
Attackers can exploit unsanitized language and namespace parameters to perform path traversal or SSRF, potentially reading sensitive files or accessing internal services.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-42353?
CVE-2026-42353 is a high-severity path traversal vulnerability in i18next-http-middleware, published on 8 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
i18next-http-middleware is a middleware to be used with Node.js web frameworks like express or Fastify and also for Deno. Prior to version 3.9.3, i18next-http-middleware passes the user-controlled lng and ns values from getResourcesHandler directly into i18next.services.backendConnector.load(languages, namespaces, …) without any sanitization. Depending on which backend is configured, the unvalidated path segments enable either path traversal or SSRF. This issue has been patched in version 3.9.3.
Which versions are affected by CVE-2026-42353?
2 open source packages ship an affected version, including i18next-http-middleware.
| Package | Affected | Fixed in |
|---|---|---|
i18next-http-middleware npm | All versions | 3.9.3 |
i18next-http-middleware npm | All versions | 3.9.3 |
How do I fix CVE-2026-42353?
Upgrade i18next-http-middleware to 3.9.3 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-42353 being exploited?
There is no known exploitation of CVE-2026-42353 in the wild and no public exploit code.
Sources
Also known as GHSA-jfgf-83c5-2c4m.