CVE-2026-75985 Overview
CVE-2026-75985 is a command injection vulnerability affecting TRENDnet Router firmware version 1.1.02b01. The flaw resides in an unknown function within /cgi-bin/ping.cgi. Attackers can manipulate the wan_type argument to inject arbitrary operating system commands. The vulnerability is exploitable remotely over the network and requires low privileges. A public proof-of-concept exploit has been released, increasing the risk of opportunistic attacks against exposed devices. This weakness is classified under [CWE-74] (Improper Neutralization of Special Elements in Output Used by a Downstream Component).
Critical Impact
Remote attackers with low privileges can inject arbitrary commands through the wan_type parameter of ping.cgi, potentially compromising the router.
Affected Products
- TRENDnet Router firmware version 1.1.02b01
- /cgi-bin/ping.cgi component
- Devices exposing the web management interface to untrusted networks
Discovery Timeline
- 2026-08-19 - CVE-2026-75985 published to NVD
- 2026-08-20 - Last updated in NVD database
Technical Details for CVE-2026-75985
Vulnerability Analysis
The vulnerability affects the ping.cgi handler exposed by the TRENDnet Router web interface. The handler consumes the wan_type HTTP parameter and passes it into a downstream shell context without sufficient neutralization of shell metacharacters. As a result, an authenticated user with low privileges can append arbitrary shell commands to the parameter value. These commands execute in the context of the router's web service, which on embedded devices typically runs with elevated system privileges.
The public proof-of-concept demonstrates the injection path against /cgi-bin/ping.cgi. Because the router exposes this endpoint over HTTP, exploitation does not require local access. Successful command injection can lead to configuration tampering, credential theft from the device, pivoting into the LAN, or installation of persistent implants on the firmware.
Root Cause
The root cause is improper neutralization of special elements in the wan_type parameter before it is used in a command string [CWE-74]. The CGI script concatenates user-controlled input into a shell invocation instead of using safe argument passing or an allow-list of expected values.
Attack Vector
Exploitation occurs over the network against the router's management interface. The attacker submits a crafted HTTP request to /cgi-bin/ping.cgi containing shell metacharacters in the wan_type argument. Low-privilege credentials are required, but many deployments retain default or weak credentials. Technical details are documented in the VulDB CVE Entry and the GitHub PoC Script.
Detection Methods for CVE-2026-75985
Indicators of Compromise
- HTTP requests to /cgi-bin/ping.cgi containing shell metacharacters such as ;, |, &, backticks, or $() in the wan_type parameter
- Unexpected outbound connections originating from the router to attacker-controlled infrastructure
- New or modified processes on the router, including reverse shells or downloader utilities such as wget or curl
Detection Strategies
- Inspect web server and reverse proxy logs for POST or GET requests to ping.cgi with abnormal wan_type values
- Deploy network intrusion detection signatures that match command injection patterns targeting the CGI endpoint
- Correlate authentication events with subsequent management-plane requests to spot low-privilege accounts touching diagnostic endpoints
Monitoring Recommendations
- Forward router syslog and HTTP access logs to a central SIEM for longitudinal analysis
- Alert on any administrative traffic to the router originating from non-management network segments
- Monitor for firmware or configuration checksum changes on managed TRENDnet devices
How to Mitigate CVE-2026-75985
Immediate Actions Required
- Restrict access to the router management interface to trusted management VLANs or hosts
- Disable remote WAN-side administration if it is not required
- Rotate all router credentials and remove default or shared accounts that could be leveraged for the low-privilege prerequisite
- Audit HTTP logs for prior exploitation attempts against /cgi-bin/ping.cgi
Patch Information
No vendor patch has been referenced in the available advisories at publication time. Refer to the VulDB Vulnerability Details page for updates and to the vendor's support channels for firmware releases addressing the ping.cgi command injection.
Workarounds
- Place the router behind a network segmentation boundary that blocks HTTP access to /cgi-bin/ping.cgi from user networks
- Use an upstream web application firewall or reverse proxy to filter requests containing shell metacharacters in the wan_type parameter
- Replace end-of-life or unpatched devices with supported models where firmware updates are actively maintained
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
