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OS Command InjectionWeakness · CWE-78

CVE-2026-59800

CRITICAL · 9.8 CVSS v3.1 Published 2026-07-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click 7 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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).

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

9Router before 0.4.44 has an OS command injection vulnerability in the unauthenticated POST /api/tunnel/tailscale-install endpoint. The sudoPassword field from the request body is written to stdin of a 'sudo -S sh' child process, and when sudo does not prompt for a password (root user, NOPASSWD configured, or cached timestamp), the attacker-supplied sudoPassword value is interpreted by sh as shell commands, allowing unauthenticated remote arbitrary OS command execution.

MitigationUpgrade to 9Router 0.4.44 or later. Until patched, block access to /api/tunnel/tailscale-install at the network perimeter and verify sudo does not have NOPASSWD entries for the affected process.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Determine 9Router installed version
    Locate the 9Router installation and retrieve its version number using package manager queries, binary metadata inspection, or service version reporting. Compare your version against the affected range (versions before 0.4.44).
    Affected if Your 9Router version is lower than 0.4.44
  2. Verify /api/tunnel/tailscale-install endpoint is network-accessible
    Test network access to the /api/tunnel/tailscale-install endpoint from untrusted network perspectives. This is the specific endpoint that contains the command injection flaw.
    Affected if The endpoint is exposed to untrusted or public network segments without authentication requirements
  3. Examine sudo policy for the 9Router service account
    Review the sudoers configuration and sudo policy on the system running 9Router. Determine whether the account running 9Router or related sudo operations has NOPASSWD privileges, runs as root, or maintains cached sudo timestamps that would bypass password prompts.
    Affected if Sudo can execute commands without requiring a password for the relevant user context

Your environment is affected if 9Router version is below 0.4.44 AND the /api/tunnel/tailscale-install endpoint is network-accessible AND sudo does not require password authentication for the executing user.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to 9Router 0.4.44 or later. Until patched, block access to /api/tunnel/tailscale-install at the network perimeter and verify sudo does not have NOPASSWD entries for the affected process.

Recommended fix High confidence

9Router 0.4.44

  1. 1. Back up the current 9Router configuration and data
  2. 2. Check current installed version (e.g., via '9router --version' or package manager)
  3. 3. Upgrade to 9Router version 0.4.44 or later using the project's official upgrade procedure
  4. 4. Verify the new version is running post-upgrade
  5. 5. Review sudo configuration to ensure NOPASSWD is intentionally configured and restrict sudo access as per least-privilege principle

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-59800 in production — separate from our analysis above.

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