CVE-2026-108894 Overview
CVE-2026-108894 is an OS command injection vulnerability in the Linksys E1700 router running firmware version 1.0.0.4.003. The flaw resides in the addStaticRoute function of the /goform/addStaticRoute endpoint, part of the Static Route Handler component. Attackers can manipulate the staticRoute_IP_setting, staticRoute_Netmask_setting, staticRoute_Gateway_setting, or staticRoute_Metric_setting parameters to inject arbitrary operating system commands. Remote exploitation is possible, and the exploit has been publicly released. The vendor was contacted prior to disclosure but did not respond. The weakness is classified under CWE-77: Improper Neutralization of Special Elements used in a Command.
Critical Impact
Authenticated remote attackers can execute arbitrary OS commands on the router, achieving full device compromise and establishing a foothold on the internal network.
Affected Products
- Linksys E1700 router
- Firmware version 1.0.0.4.003
- Static Route Handler component (/goform/addStaticRoute)
Discovery Timeline
- 2026-10-12 - CVE-2026-108894 published to NVD
- 2026-10-14 - Last updated in NVD database
Technical Details for CVE-2026-108894
Vulnerability Analysis
The vulnerability exists in the addStaticRoute function handling HTTP POST requests to the /goform/addStaticRoute URI. The function reads four user-controlled parameters that represent the static route configuration: IP address, netmask, gateway, and metric. These values are passed to an underlying shell command without proper neutralization of shell metacharacters. An attacker able to reach the router's web management interface can append shell operators such as ;, |, or backticks to any of the four parameters. The injected payload executes with the privileges of the web server process, which on consumer routers typically runs as root. Successful exploitation yields full command execution on the embedded Linux system, enabling firmware modification, credential theft, DNS hijacking, and lateral movement.
Root Cause
The root cause is improper neutralization of special elements used in a command [CWE-77]. The addStaticRoute handler constructs a system command by concatenating raw request parameters into a shell invocation. No input validation enforces numeric or dotted-quad formats, and no escaping is applied before the string reaches the shell interpreter.
Attack Vector
Exploitation is network-based and requires low-privileged authentication to the router's web interface. An attacker submits a crafted POST request to /goform/addStaticRoute with a payload embedded in one of the four staticRoute_*_setting fields. Because the exploit is publicly available, opportunistic scanning and automated weaponization are likely. Full technical details are published in the GitHub vulnerability writeup and the VulDB entry for CVE-2026-108894.
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Stop Exploit AttemptsDetection Methods for CVE-2026-108894
Indicators of Compromise
- HTTP POST requests to /goform/addStaticRoute containing shell metacharacters such as ;, |, &, `, or $( within the staticRoute_IP_setting, staticRoute_Netmask_setting, staticRoute_Gateway_setting, or staticRoute_Metric_setting parameters.
- Unexpected outbound connections originating from the router to attacker-controlled infrastructure.
- Unauthorized modifications to router configuration, DNS settings, or firmware integrity.
Detection Strategies
- Deploy network IDS signatures that inspect POST bodies to /goform/addStaticRoute for non-IPv4 content in the route parameters.
- Enable web server access logging on the router where supported and forward logs to a central SIEM for correlation.
- Monitor for anomalous process execution on the gateway, such as wget, curl, nc, or sh spawned by the web daemon.
Monitoring Recommendations
- Baseline normal administrative traffic to the router and alert on route-table changes outside maintenance windows.
- Correlate router log data with endpoint telemetry to identify downstream compromise following gateway exploitation.
- Track EPSS trends for this CVE, currently at a probability of 2.157% and the 81.8th percentile, to prioritize patch urgency.
How to Mitigate CVE-2026-108894
Immediate Actions Required
- Restrict access to the router's web management interface to trusted internal hosts only and disable WAN-side administration.
- Rotate the router administrator password and enforce strong, unique credentials to reduce the risk of authenticated exploitation.
- Audit the current static route table and remove entries that were not added by authorized administrators.
Patch Information
No vendor patch is available. According to the NVD entry, Linksys was contacted prior to public disclosure but did not respond. Organizations operating the affected Linksys E1700 running firmware 1.0.0.4.003 should treat the device as unpatched and plan replacement with a supported platform. Monitor the Linksys official website for future firmware updates.
Workarounds
- Place the Linksys E1700 behind a network segmentation boundary that blocks untrusted hosts from reaching the management interface.
- Disable remote administration features and require VPN access for any configuration changes.
- Replace end-of-support or unresponsive-vendor devices with hardware that receives active security maintenance.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
