How broadly exploitable is this vulnerability?

Exploitability depends on how the echo server functionality is exposed. If the interface that accepts the port parameter is reachable from untrusted networks (for example, if the router's management interface is accessible from the WAN), remote attackers may exploit it without prior compromise. If exposure is limited to the LAN, attackers must first gain access to the local network or a position where they can send requests to the device.

Does exploitation require authentication or privileged access?

Not necessarily. If the endpoint that triggers enable_echo_server is unauthenticated or weakly protected, an attacker can abuse it directly. If it sits behind authentication, an attacker would need to obtain valid credentials or exploit another weakness to reach the vulnerable code path.

What is the safest general fix pattern for developers or firmware maintainers?

The most robust fix is to eliminate shell-based command construction entirely. Use system libraries or APIs that configure the echo server directly or invoke external programs via parameterized exec-style calls, never interpolating untrusted strings into shell commands. Combine this with strict validation that only allows expected numeric port values.

Severity:

CRITICAL RISK

(9.8)

OS Command Injection (CWE-77) in GL-iNet GL-AR300M16 Echo Server Handler

CVE-2026-26791

Published:

Mar 12, 2026

Status:

Modified

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

NDV

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Privilege Escalation via Bypassed Access Control

May 6, 2026

Vulnerability Type

Category:

OS Command Injection

CWE:

CWE-77

Impact:

Remote Code Execution on Embedded Network Device

Severity:

CRITICAL RISK

(9.8)

CVSS Version:

3.1

Vulnerability Type

Category:

OS Command Injection

CWE:

CWE-77

Impact:

Remote Code Execution on Embedded Network Device

Severity:

CRITICAL RISK

(9.8)

CVSS Version:

3.1

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OS Command Injection (CWE-77) in GL-iNet GL-AR300M16 Echo Server Handler

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

Recent Vulnerabilities

HIGH RISK

HIGH

(8.6)

Server-Side Request Forgery (CWE-918) in OpenClaw Zalo Plugin sendPhoto

HIGH RISK

HIGH

(8.8)

Authorization Bypass (CWE-863) in OpenClaw Matrix Room Control Commands

Vulnerability Type

Vulnerability Type

Vulnerability Type

Catch This CVE While Code Is Being Written

Ship clean & secure code faster

Ship clean & secure code faster

Ship clean & secure code faster

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