Path Traversal in i18next-fs-backend (CVE-2026-41693)
Summary
Path traversal in i18next-fs-backend (CVE-2026-41693). Confidential information can be exposed externally. Exploitable via lng. Mitigation: upgrade to 2.6.4 or later.
Original description
The description as published by the source.
i18next-fs-backend is a backend layer for i18next using in Node.js and for Deno to load translations from the filesystem. Prior to version 2.6.4, i18next-fs-backend substitutes the lng and ns options directly into the configured loadPath / addPath templates and then read / write the resulting file from disk. The interpolation is unencoded and unvalidated, so a crafted lng or ns value — containing .., a path separator, a control character, a prototype key, or simply an unexpectedly long string — allows an attacker who can influence either value to read or overwrite files outside the intended locale directory. When lng / ns are derived from untrusted input (request-scoped i18next instances behind an HTTP layer such as i18next-http-middleware, or any framework that lets the end user pick the language via query string, cookie, or header), a single request such as ?lng=../../../../etc/passwd causes the backend to attempt to read that path. This issue has been patched in version 2.6.4.
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-2026-41693 has been found in i18next-fs-backend.
Attackers can target a specific entry point like lng over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 8.2/10.
What to do: upgrade i18next-fs-backend to 2.6.4 or later.
If unsure, ask your IT team or search "i18next-fs-backend CVE-2026-41693" on the vendor's site.
CVE-2026-41693 (i18next-fs-backend) — CWE-22 / CVSS v3 8.2
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: lng / loadPath / addPath / read
Patched: 2.6.4 — 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.
Path traversal (CWE-22) exists in i18next-fs-backend. Attackers reach the vulnerable code path via lng without authentication.
Check the vendor advisory for the affected versions of i18next-fs-backend. Attack surface: lng / loadPath / addPath / read.
Severity: High (CVSS 8.2/10). Confidential information can be exposed externally.
Update to 2.6.4.
Workaround: No workaround short of upgrading.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'i18next-fs-backend' . 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-fs-backend' . | 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-fs-backendを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply 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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3Apply patch patch
Upgrade i18next-fs-backend to 2.6.4ステージング環境で 2.6.4 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を含めること。
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4Post-deployment verification verify
Confirm patched version is live in production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。本番ではアクセスログ・WAF 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 github.com