Cyber Posture

CVE-2026-26791

CriticalPublic PoC

Published: 12 March 2026

Published
12 March 2026
Modified
16 March 2026
KEV Added
—
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 0.0107 77.8th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

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.

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.

Security SummaryAI

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.

Details

CWE(s)
CWE-77

Affected Products

gl-inet
ar300m16 firmware
4.3.11

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

References