CVE-2026-41690

CVE-2026-41690 · Prototype pollution and path traversal in i18next-http-middleware via user-controlled language and namespace parameters

This page contains facts from public vulnerability sources. Check the original advisory before updating.

18next-http-middleware is a middleware to be used with Node.js web frameworks like express or Fastify and also for Deno. Versions prior to 3.9.3 allow an unauthenticated HTTP client to pollute Object.prototype in the Node.js process hosting the middleware, via two unvalidated entry points that reach internal object-key writes: getResourcesHandler and missingKeyHandler. This can break authorisation checks (if (user.isAdmin) returning true for any user), cause type-confusion DoS, and depending on downstream code it can be chained into RCE.

CVSS 8.6 · High · EPSS 0.3% · Fix available

Published

2026-05-08T15:24:12.014Z

Updated

2026-05-08T16:43:48.281Z

Stack: node

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