{"cve":"CVE-2026-41690","nvd":{"published":"2026-05-08T16:16:11.473","modified":"2026-10-26T18:10:00.173","status":"Deferred","description":"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_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L","score":8.6},"cwes":["CWE-22","CWE-1321"],"references":["https://github.com/i18next/i18next-http-middleware/security/advisories/GHSA-5fgg-jcpf-8jjw"],"products":[],"source":"nvd","synced_at":"2026-10-26T18:27:13.530666824+00:00"},"epss":{"cve":"CVE-2026-41690","score":0.0031,"percentile":0.23683,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-5fgg-jcpf-8jjw","url":"https://osv.dev/vulnerability/GHSA-5fgg-jcpf-8jjw","summary":"i18next-http-middleware: Prototype pollution and path traversal via user-controlled language and namespace parameters","modified":"2026-05-13T13:56:02.081799Z","packages":[{"ecosystem":"npm","name":"i18next-http-middleware","purl":"pkg:npm/i18next-http-middleware","ranges":["<3.9.3"],"fixed":["3.9.3"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}