CVE-2026-59800: Command Injection (CVSS 9.8)

Description

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).

Is your site exposed to CVE-2026-59800?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0137

Probability of exploitation

0.69%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-78 OS Command Injection

References

Other References

https://github.com/decolua/9router/security/advisories/GHSA-g6g7-pvmx-m74p https://www.vulncheck.com/advisories/9router-os-command-injection-via-sudopassword-parameter-in-tailscale-install-endpoint https://github.com/decolua/9router/security/advisories/GHSA-g6g7-pvmx-m74p

Frequently Asked Questions

What is CVE-2026-59800? +

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). It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-59800? +

CVE-2026-59800 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0137, placing it in the 1th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-59800? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2024-54012

Penetration Testing engineers at Amazon discovered a vulnerability where the camera system failed to properly validate input, allowing specially crafted …

CVE-2026-8652

An OS Command Injection vulnerability exists in Aterm. If a malicious third person gains administrator access to the product’s web …

CVE-2025-13605

3onedata modbus gateway device model GW1101-1D(RS-485)-TB-P (hardware version V2.2.0) allows authenticated users to execute arbitrary shell commands in the context …

CVE-2026-41925

WDR201A WiFi Extender (HW V2.1, FW LFMZX28040922V1.02) contains an OS command injection vulnerability in the adm.cgi binary's reboot_time function that …

CVE-2026-41924

WDR201A WiFi Extender (HW V2.1, FW LFMZX28040922V1.02) contains an OS command injection vulnerability in the makeRequest.cgi binary that allows unauthenticated …

CVE-2026-41923

WDR201A WiFi Extender (HW V2.1, FW LFMZX28040922V1.02) contains an OS command injection vulnerability in the internet.cgi binary that allows unauthenticated …

CVE-2026-59800