CVE-2026-90847: EFM ipTIME C200E RCE Vulnerability

CVE-2026-90847 Overview

CVE-2026-90847 is an operating system command injection vulnerability in the EFM ipTIME C200E router, firmware version 1.094. The flaw resides in an unknown function within the iux_set.cgi script, part of the device's System Setup component. Authenticated attackers can inject arbitrary operating system commands remotely over the network. The vulnerability is classified under CWE-77: Improper Neutralization of Special Elements used in a Command. Public disclosure of exploit details has occurred, increasing the risk of active exploitation against exposed devices.

Critical Impact
Successful exploitation allows attackers with high privileges to execute arbitrary OS commands on the router, compromising confidentiality, integrity, and availability of the device and any downstream network segments.

Affected Products

EFM ipTIME C200E firmware version 1.094
Component: System Setup (iux_set.cgi)
Deployments exposing the web management interface to untrusted networks

Discovery Timeline

2026-09-15 - CVE-2026-90847 published to the National Vulnerability Database (NVD)
2026-09-15 - Last updated in NVD database

Technical Details for CVE-2026-90847

Vulnerability Analysis

The vulnerability affects the iux_set.cgi handler responsible for processing System Setup requests on the ipTIME C200E router. Input passed to this endpoint is incorporated into an OS command string without adequate neutralization of shell metacharacters. Attackers can append or inject commands that execute in the context of the underlying router process, typically running with elevated privileges.

Because the attack is delivered over the network and requires no user interaction, exploitation can be scripted at scale. The EPSS exploit prediction places this issue in the upper tier of network-facing bugs, and technical details have been publicly released through VulDB and a video walkthrough.

Root Cause

The root cause is improper neutralization of special elements used in an OS command [CWE-77]. The iux_set.cgi component concatenates attacker-controlled parameters into a shell command invocation. Metacharacters such as ;, |, &&, and backticks are not filtered or escaped, allowing arbitrary command chaining.

Attack Vector

Exploitation requires network access to the router's management interface and authenticated access with high privileges (PR:H). The attacker submits a crafted HTTP request to iux_set.cgi containing shell metacharacters within a parameter processed by the vulnerable function. The injected command executes on the device with router-level privileges, enabling firmware modification, credential theft, traffic interception, and pivoting into internal networks.

No verified exploit code has been released to this article's sources. See the VulDB entry for CVE-2026-90847 and the associated video analysis for technical proof-of-concept detail.

Detection Methods for CVE-2026-90847

Indicators of Compromise

HTTP POST or GET requests to iux_set.cgi containing shell metacharacters such as ;, |, &, $(), or backticks in parameter values.
Unexpected outbound connections initiated from the router to attacker-controlled infrastructure.
Unauthorized changes to router configuration, DNS settings, or firmware versions on affected ipTIME C200E devices.

Detection Strategies

Inspect web server and CGI request logs on the router for anomalous parameter content targeting iux_set.cgi.
Deploy network intrusion detection signatures matching command-injection payload patterns on HTTP traffic destined for router management ports.
Correlate administrative authentication events with subsequent configuration changes to identify misuse of privileged sessions.

Monitoring Recommendations

Baseline normal administrative traffic to router management interfaces and alert on deviations.
Monitor DNS and outbound traffic patterns from router IP addresses for signs of command-and-control communication.
Track firmware integrity and configuration state on ipTIME devices, alerting on unauthorized modifications.

How to Mitigate CVE-2026-90847

Immediate Actions Required

Restrict access to the ipTIME C200E web management interface to trusted internal management networks only.
Disable remote (WAN-side) administration on all ipTIME C200E devices until a vendor patch is applied.
Rotate all administrative credentials on affected routers and enforce strong, unique passwords.
Audit device configurations and firmware for signs of unauthorized modification.

Patch Information

No vendor patch has been referenced in the available advisory data at the time of publication. Administrators should monitor the EFM ipTIME support portal and the VulDB advisory for CVE-2026-90847 for updated firmware releases addressing this issue.

Workarounds

Place affected routers behind a network segment that blocks untrusted access to management ports (default TCP/80 and TCP/443).
Enforce access control lists on upstream firewalls to permit management traffic only from designated administrator IP addresses.
Where possible, replace or retire end-of-support ipTIME C200E devices with actively supported hardware.

bash

# Configuration example: restrict router management access with iptables
iptables -A INPUT -p tcp --dport 80 -s 192.0.2.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -s 192.0.2.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP