Vulnerability in i18next-http-middleware (CVE-2026-41690)
Summary
Vulnerability in i18next-http-middleware (CVE-2026-41690). Data can be tampered with by attackers. Exploitable via GET /locales/resources.json. Mitigation: upgrade to 3.9.3 or later.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-41690 has been found in i18next-http-middleware.
Attackers can target a specific entry point like GET /locales/resources.json over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 8.6/10.
What to do: upgrade i18next-http-middleware to 3.9.3 or later.
If unsure, ask your IT team or search "i18next-http-middleware CVE-2026-41690" on the vendor's site.
CVE-2026-41690 (i18next-http-middleware) — CWE-1321 / CVSS v3 8.6
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: GET /locales/resources.json / lng / getResourcesHandler / setPath
Patched: 3.9.3 — apply immediately
Workaround: No workaround short of upgrading.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-1321) exists in i18next-http-middleware. Attackers reach the vulnerable code path via GET /locales/resources.json without authentication.
Check the vendor advisory for the affected versions of i18next-http-middleware. Attack surface: GET /locales/resources.json / lng / getResourcesHandler / setPath.
Severity: High (CVSS 8.6/10). Data can be tampered with by attackers.
Update to 3.9.3.
Workaround: No workaround short of upgrading.
Search webserver/proxy logs for unusual GET /locales/resources.json requests with malformed payloads or SQL meta-characters. Run grep -r 'i18next-http-middleware' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'i18next-http-middleware' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
i18next-http-middlewareを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'GET /locales/resources.json' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
GET /locales/resources.jsonへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply temporary workaround mitigate
No workaround short of upgrading.パッチが適用されるまでの応急処置として、No workaround short of upgrading. を実施。回避策の副作用 (機能低下) を確認した上で。
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4Apply patch patch
Upgrade i18next-http-middleware to 3.9.3ステージング環境で 3.9.3 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。
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5Post-deployment verification verify
Replay attack against GET /locales/resources.json on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- web i18next.com
- web github.com