CVE-2025-5000 in FGW3000-AH
Summary
by MITRE • 05/21/2025
A vulnerability was found in Linksys FGW3000-AH and FGW3000-HK up to 1.0.17.000000. It has been classified as critical. This affects the function control_panel_sw of the file /cgi-bin/sysconf.cgi of the component HTTP POST Request Handler. The manipulation of the argument filename leads to command injection. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
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Analysis
by VulDB Data Team • 05/21/2025
This vulnerability resides in the Linksys FGW3000-AH and FGW3000-HK network appliances, specifically within the HTTP POST Request Handler component that processes system configuration requests through the /cgi-bin/sysconf.cgi interface. The flaw manifests in the control_panel_sw function where the filename parameter is improperly handled, creating a command injection vulnerability that allows attackers to execute arbitrary commands on the affected devices. The vulnerability has been classified as critical due to its remote exploitability and the potential for complete system compromise, making it a significant threat to network security infrastructure. The issue affects firmware versions up to 1.0.17.000000, indicating a widespread problem across multiple device models that share the same vulnerable codebase.
The technical nature of this vulnerability aligns with CWE-77, which describes command injection flaws where untrusted input is directly incorporated into operating system commands without proper validation or sanitization. The attack vector is particularly concerning as it operates through HTTP POST requests, meaning an attacker can exploit this vulnerability remotely without requiring physical access to the device. The filename parameter serves as the injection point where malicious input can be crafted to execute arbitrary shell commands, potentially allowing threat actors to gain root access to the appliance and control all network traffic passing through it. This type of vulnerability represents a fundamental breakdown in input validation and output encoding practices within the web application layer.
The operational impact of this vulnerability extends beyond simple device compromise, as it provides attackers with complete control over the network gateway appliance. Once exploited, threat actors can manipulate network traffic, redirect connections, establish backdoors, or use the device as a pivot point for attacking internal network resources. The fact that this vulnerability has been publicly disclosed and is actively being used in the wild increases the urgency for remediation, as it represents a known attack pattern that security teams must prepare to defend against. Network administrators face the challenge of securing critical infrastructure components that may already be compromised, requiring immediate assessment of device inventories and implementation of protective measures.
Organizations should implement immediate mitigations including network segmentation to isolate affected devices, disabling unnecessary services, and applying firmware updates once available from the vendor. The lack of vendor response to early disclosure attempts creates additional risk as there may be no official patch or workaround provided by the manufacturer. Security teams should monitor for exploitation attempts through network traffic analysis, intrusion detection systems, and log reviews for suspicious POST requests to the sysconf.cgi endpoint. This vulnerability demonstrates the importance of maintaining updated firmware, implementing network monitoring, and following security best practices such as the principle of least privilege and regular security assessments. The ATT&CK framework would classify this as a privilege escalation and command execution technique, with potential for lateral movement through the compromised network gateway.