Vulnerability report

Active exploitation observed Confirmed confidence Not in CISA KEV

CVE-2026-59800

9router < 0.4.44 OS Command Injection

Decolua / 9router · affected before 0.4.44

Watch CVE-2026-59800 Browse KEV feed
Severity
CVSS 9.2 · Critical
Confidence
Confirmed
Exploit status
Observed in sensors
EPSS
2.0%
First observed
10 Jul 2026
Last observed
14 Jul 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-59800 is an unauthenticated vulnerability affecting Decolua 9router. 9Router before 0.4.44 contains an OS command injection vulnerability in the unauthenticated POST /api/tunnel/tailscale-install endpoint...

Is it exploited?

Yes. Previdian sensors observed exploitation attempts with confirmed confidence. Also confirmed by third-party sources.

Who is affected?

Decolua / 9router affected before 0.4.44.

What should we do?

Patch immediately, validate internet-facing exposure, and monitor for matching requests.

Overview

9router < 0.4.44 OS Command Injection

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).

decolua Affected
9router
Before 0.4.44
decolua Unaffected
9router
0.4.44
View vendor advisory (opens in new tab)
Published
07 Jul 2026
Exploited Since
10 Jul 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

edge

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

The Shadowserver

Recorded 31 Jul 2026

Previdian independently recorded this as exploited after first seeing it in honeypot sensors.

Active exploitation observed

Previdian sensor

First observed 13 Jul 2026

Previdian first observed exploitation attempts targeting this vulnerability in our honeypot sensors.

Proof of concept available

Pruva

Recorded 08 Jul 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
The Shadowserver First 2026-07-31 00:00 UTC
Previdian Sensors 2026-08-01 11:09 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Previdian sensors recorded exploitation attempts targeting this vulnerability. The cards and chart show volume, unique attackers, and daily activity.

0

Attempts observed

0

Unique attacker IPs

—

Attacker countries

—

Sensors observed

CVE-2026-59800 exploitation attempts over the last 91 days

Daily events observed by Previdian sensors

Updated 16 Oct 2026

No daily activity in the retention window.

First observed 10 Jul 2026 · Last observed 14 Jul 2026

Pro adds sensor region and window summaries. Enterprise adds raw IPs, paths, User-Agents, and payloads.

Start 14-day Pro trial

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
1

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Attacker IP Indicators

Attacker IP indicators observed · available in Pro and Enterprise.

Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.

Learn about Pro API access

Risk and context

Severity, weaknesses, and research context

CVSS v4.0

9.2 Critical

Potential damage if exploited. Separate from whether attackers are using it.

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

EPSS

2.0%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') CWE-78

Recent mention · RecordedFuture

August 2026 CVE Landscape

In August 2026, Insikt Group® identified 73 high-impact vulnerabilities that should be prioritized for remediation, 43 of which had a Very Critical Recorded Future Risk Score. This represents a 14% decrease from last month.

Read full advisory

All CVSS Scores

CVSS v4.0 9.2 Critical

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

CVSS v3.1 9.8 Critical

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

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

9router before 0.4.44 allows unauthenticated remote OS command execution via the /api/tunnel/tailscale-install endpoint by injecting shell commands in the sudoPassword field when sudo does not prompt for a password.

pruva · Created 2026-07-08 04:50:47 UTC

Severity: CRITICAL | CVE: CVE-2026-59800 | Package: 9router (npm)

Timeline

From disclosure to observed exploitation

  1. 00:00 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party attested exploitation

  2. 06:46 UTC

    Observed by Previdian sensors

    Evidence-backed exploitation signal

  3. 11:22 UTC

    Indicators of compromise added (3)

    Indicators of compromise recorded

  4. 04:50 UTC

    Public PoC available

    Public proof-of-concept code published

  5. 18:19 UTC

    CVE published

    Vulnerability disclosed publicly

  6. 14:39 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

Start 14-day Pro trial Read API docs
  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-59800

Sample API response 
{
  "cve_id": "CVE-2026-59800",
  "confidence": "Confirmed",
  "cvss_score": 9.2,
  "cvss_estimated": false,
  "epss_score": 0.02043,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}