Cyber Posture

CVE-2026-9387

CriticalRCE
Microsoft: not affectedMSmacOS: not affectedMacLinux: not affectedLnxMobile: not affectedMobNetwork: not affectedNetApplication: not affectedAppOther: affectedOth

Published: 24 May 2026

Published
24 May 2026
Modified
26 May 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 0.0089 75.9th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-9387 is a critical-severity Command Injection (CWE-77) vulnerability in Totolink A8000RU (inferred from references). 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 24.1% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 1 other technique.
Deeper analysisAI

Automated synthesis unavailable for this CVE.

Vulnerability

A security flaw has been discovered in Totolink A8000RU 7.1cu.643_b20200521. The affected element is the function setUpgradeFW of the file /cgi-bin/cstecgi.cgi of the component Web Management Interface. Performing a manipulation of the argument resetFlags results in os command injection. It…

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is possible to initiate the attack remotely. The exploit has been released to the public and may be used for attacks.

CWE(s)
CWE-77CWE-78
OWASP Top 10 Web 2025
A05:2025

EU & UK References

Regulatory context (EU CRA / NIS2 / DORA / UK NIS Regulations)

EU Cyber Resilience Act — coordinated disclosure

Critical and high-severity vulnerabilities in products with digital elements may trigger coordinated-disclosure obligations under the EU Cyber Resilience Act (CRA, Regulation 2024/2847). Manufacturers placing products on the EU market must notify ENISA and the relevant CSIRTs without undue delay once active exploitation is known.

Affected Products

Totolink
A8000RU
inferred from references and description; NVD did not file a CPE for this CVE

Threat picture

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 →
T1059.004 Unix Shell Execution
Adversaries may abuse Unix shell commands and scripts for execution.
attack.mitre.org →
Why these techniques?

Remote OS command injection in web management interface (setUpgradeFW/resetFlags) directly enables T1190 exploitation of public-facing app and T1059.004 Unix shell command execution.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

Defense & controls

Likely Mitigating ControlsAI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SC-27 Platform-independent Applications
addresses: CWE-78

Platform-independent apps typically execute inside a managed runtime or sandbox that restricts direct OS command execution, reducing the ability to exploit OS command injection.

SI-10 Information Input Validation
addresses: CWE-78

Validates inputs to block special elements that would alter OS command execution.

References