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High 8.6Published May 8, 2026

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

Updated under an hour ago ()

Does this affect you?

It affects i18next-http-middleware. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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 (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L
Weakness (CWE)
CWE-22, CWE-1321
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Deferred
Record last updated
May 8, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
i18next i18next-http-middleware
i18next:http_middleware (from the name)
before 3.9.3
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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