---
title: "CVE-2026-59800: 9router: Missing Authorization and OS Command Injection"
url: https://erroneo.us/security/cve/CVE-2026-59800/
description: "CVE-2026-59800 (9router (npm)): 9Router before 0.4.44 contains an OS command injection vulnerability in the unauthenticated POST…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-07-07
date_modified: 2026-07-07
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-59800"
kev: false
cvss: 9.2
epss: 0.02043
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-59800: 9router: Missing Authorization and OS Command Injection

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 2.0% , percentile 81: FIRST’s model estimates a 2.0% chance of exploitation activity in the next 30 days, higher than 81% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes 9router (npm) < 0.4.44, fixed in 0.4.44 . Check your lockfile, including transitive dependencies.

## What it is

9Router before 0.4.44 contains an OS command injection vulnerability in the unauthenticated POST /api/tunnel/tailscale-install endpoint (this route is not covered by the dashboard middleware matcher, so no authorization check is applied). The sudoPassword field from the request body is written to the stdin of a 'sudo -S sh' child process. When sudo does not prompt for a password (the process runs as root, NOPASSWD is configured, or a recent sudo timestamp cache exists), the sudoPassword value is interpreted by sh as a shell command, allowing a remote unauthenticated attacker to execute arbitrary OS commands. Exploitation evidence was first observed by the Shadowserver Foundation on 2026-07-04 (UTC).

## Affected packages

- npm `9router` < 0.4.44 → fixed: 0.4.44

## Affected products (CVE record)

- decolua 9router: < 0.4.44

## Severity

- VulnCheck CVSS 4.0: 9.2 `CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`
- VulnCheck CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 4.0: 9.2 `CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 2.04% probability of exploitation activity in the next 30 days; percentile 81.

## Sources

- [GitHub Security Advisory (GHSA-g6g7-pvmx-m74p)](https://github.com/decolua/9router/security/advisories/GHSA-g6g7-pvmx-m74p)
- [GitHub Advisory GHSA-g6g7-pvmx-m74p](https://github.com/advisories/GHSA-g6g7-pvmx-m74p)
- [CVE.org record CVE-2026-59800](https://www.cve.org/CVERecord?id=CVE-2026-59800)
- [NVD entry CVE-2026-59800](https://nvd.nist.gov/vuln/detail/CVE-2026-59800)
- [vulncheck.com](https://www.vulncheck.com/advisories/9router-os-command-injection-via-sudopassword-parameter-in-tailscale-install-endpoint)
- [github.com](https://github.com/decolua/9router/releases?q=0.4.44&expanded=true)

---
Source page: https://erroneo.us/security/cve/CVE-2026-59800/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt