CVE-2026-58147 Overview
CVE-2026-58147 is an operating system command injection vulnerability [CWE-78] in the WNC T-Mobile 5G Box IDU router. The flaw resides in the portal.cgi component that handles password change requests. The application fails to neutralize special characters in the http_passwd_hidden and http_passwdConfirm_hidden parameters. An authenticated attacker on an adjacent network can inject arbitrary shell commands that execute with root privileges on the router. The vendor addressed the issue in firmware version 1.1.0.651412.
Critical Impact
Successful exploitation yields root-level command execution on the router, giving an attacker full control over the device, its network traffic, and any downstream clients.
Affected Products
- WNC T-Mobile 5G Box IDU router firmware versions prior to 1.1.0.651412
- portal.cgi password change handler
- Deployments exposing the management portal to adjacent network segments
Discovery Timeline
- 2026-09-16 - CVE-2026-58147 published to NVD
- 2026-09-16 - Last updated in NVD database
Technical Details for CVE-2026-58147
Vulnerability Analysis
The vulnerability lives in the router's web management interface, specifically the portal.cgi endpoint that processes password change operations. The handler receives the new password through two hidden form fields, http_passwd_hidden and http_passwdConfirm_hidden. Instead of treating those values as opaque strings, the CGI code passes them into a shell context without sanitization. An attacker who supplies shell metacharacters such as backticks, semicolons, or $() substitutions breaks out of the intended password argument and executes attacker-controlled commands. Because portal.cgi runs as root on the embedded Linux system, injected commands inherit those privileges. The result is arbitrary code execution on the router itself, with the ability to modify configuration, install persistent implants, or pivot into connected networks.
Root Cause
The root cause is improper neutralization of special elements used in an operating system command [CWE-78]. The password change routine concatenates the http_passwd_hidden and http_passwdConfirm_hidden parameter values into a shell command string before invoking a system call. No allow-listing, escaping, or safe execution wrapper is applied, so any shell metacharacter in the input is interpreted by the underlying shell.
Attack Vector
Exploitation requires authenticated access to the portal and network adjacency to the device. An attacker with valid administrator credentials submits a crafted password change request in which the password parameters contain shell metacharacters followed by arbitrary commands. The CGI handler executes the injected payload as root. Additional technical context is available in the CERT Poland CVE-2026-40854 Analysis, which covers related issues in the same device family.
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Stop Exploit AttemptsDetection Methods for CVE-2026-58147
Indicators of Compromise
- Requests to portal.cgi containing shell metacharacters such as ;, |, `, $(, or && in the http_passwd_hidden or http_passwdConfirm_hidden parameters.
- Unexpected outbound connections originating from the router management plane following a password change request.
- New or modified files in writable firmware directories, cron entries, or startup scripts that were not created by legitimate administrative activity.
Detection Strategies
- Inspect HTTP request bodies to the router portal for non-printable or shell-significant characters inside password fields.
- Correlate authentication events with subsequent process execution telemetry on any network monitoring appliance that observes the device.
- Alert on password change requests that occur outside normal administrative windows or from unusual source addresses on the management network.
Monitoring Recommendations
- Forward router syslog and web server logs to a central log platform and retain them for post-incident review.
- Baseline expected DNS and outbound traffic from the router so that command-and-control callbacks stand out.
- Track firmware version reporting from managed devices to identify units still running versions prior to 1.1.0.651412.
How to Mitigate CVE-2026-58147
Immediate Actions Required
- Upgrade affected WNC T-Mobile 5G Box IDU routers to firmware version 1.1.0.651412 or later.
- Rotate administrator credentials on every affected device, since valid authentication is a prerequisite for exploitation.
- Restrict access to the management portal so that only trusted management VLANs or hosts can reach portal.cgi.
Patch Information
The vendor has released firmware version 1.1.0.651412, which addresses the improper neutralization of the http_passwd_hidden and http_passwdConfirm_hidden parameters in portal.cgi. Administrators should confirm the running firmware version after the update and validate that the password change workflow behaves as expected. Refer to the CERT Poland CVE-2026-40854 Analysis for additional advisory context on related device issues.
Workarounds
- Limit management portal reachability with an access control list that only permits trusted administrative hosts.
- Enforce strong, unique administrator passwords and enable account lockout policies to reduce the risk of credential compromise.
- Segment the router management interface onto an isolated VLAN separated from user and guest networks until the firmware update is applied.
# Configuration example: restrict management portal to a trusted admin subnet
# (apply on an upstream firewall or router ACL)
allow tcp from 10.10.0.0/24 to <router-mgmt-ip> port 443
deny tcp from any to <router-mgmt-ip> port 443
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
