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CVE-2026-59800
critical
CVSS 9.8
OS Command Injection in 9router (CVE-2026-59800)
Summary
OS command injection in 9router (CVE-2026-59800). Successful exploitation can lead to full system takeover. Exploitable via `POST /api/tunnel/tailscale-install`. Mitigation: upgrade to `0.4.44` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-59800** has been found in 9router.
Attackers can target a specific entry point like `POST /api/tunnel/tailscale-install` over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 9.8/10.
What to do: upgrade 9router to **0.4.44** or later.
If unsure, ask your IT team or search "9router CVE-2026-59800" on the vendor's site.
CVE-2026-59800 (9router) — CWE-78 / CVSS v3 9.8
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: POST /api/tunnel/tailscale-install / `sudoPassword` / `USER` / `systemd`
Patched: `0.4.44` — apply immediately
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.
❓ What is the problem
**OS command injection** (CWE-78) exists in 9router. Attackers reach the vulnerable code path via `POST /api/tunnel/tailscale-install` without authentication.
📍 Affected scope
9router — . Attack surface: POST /api/tunnel/tailscale-install / `sudoPassword` / `USER` / `systemd`.
🔥 Severity
Severity: Critical (CVSS 9.8/10). Successful exploitation can lead to full system takeover
🔧 How to fix
Update to **0.4.44**.
🛡️ Workaround
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
🔍 Detection
Search webserver/proxy logs for unusual `POST /api/tunnel/tailscale-install` requests with malformed payloads or SQL meta-characters. Run `grep -r '9router' .` against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response Actions (7 steps)
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r '9router' . | 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 `9router` を grep し、稼働しているサービス・バージョンを把握する。
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3Hunt for indicators of compromise detect
grep 'POST /api/tunnel/tailscale-install' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで `POST /api/tunnel/tailscale-install` 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。
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6Apply patch patch
Upgrade 9router to 0.4.44ステージング環境で 0.4.44 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 3 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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7Post-deployment verification verify
Replay attack against POST /api/tunnel/tailscale-install 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 3 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
npm
9router
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.4.44"}]}]