CVE-2026-26791

CriticalPublic PoCRCE

Published: 12 March 2026

Published

12 March 2026

Modified

16 March 2026

KEV Added

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Patch

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CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Score 0.0111 78.4th percentile

Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-26791 is a critical-severity Command Injection (CWE-77) vulnerability in Gl-Inet Ar300M16 Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 21.6% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 CM-7 (Least Functionality) and SI-10 (Information Input Validation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-10 Information Input Validation good match

prevent

Directly addresses the command injection by requiring validation of the unsanitized 'port' parameter in the enable_echo_server function to block arbitrary command execution.

SI-2 Flaw Remediation good match

prevent

Mandates timely remediation of the specific command injection flaw in the router firmware through testing and installation of patches or updates.

CM-7 Least Functionality good match

prevent

Reduces attack surface by prohibiting or restricting unnecessary functions like the vulnerable enable_echo_server, preventing exposure to remote attackers.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1059.008 Network Device CLI Execution

Adversaries may abuse scripting or built-in command line interpreters (CLI) on network devices to execute malicious command and payloads.

attack.mitre.org →

Why these techniques?

Remote unauthenticated command injection in router firmware web-exposed function enables exploitation of public-facing application (T1190) and network device CLI command execution (T1059.008).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

NVD Description

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.

Deeper analysisAI

CVE-2026-26791 is a command injection vulnerability affecting the GL-iNet GL-AR300M16 router firmware version 4.3.11. The flaw exists in the enable_echo_server function, where the string port parameter fails to properly sanitize user input, enabling attackers to inject and execute arbitrary commands via crafted inputs. Published on 2026-03-12, it is classified under CWE-77 (Command Injection) with a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

The vulnerability is exploitable by remote, unauthenticated attackers with network access to the device, requiring low complexity and no user interaction. Successful exploitation grants attackers the ability to execute arbitrary commands on the device, resulting in high impacts to confidentiality, integrity, and availability, potentially leading to full device compromise.

Additional technical details and a proof-of-concept are documented in the GitHub repository at https://github.com/sezangel/IOT-vul/tree/main/GL-iNet/GL-AR300M16/enable_echo_server. No vendor advisories or patches are referenced in the available information.