CVE-2025-41266: Waterfall WF-500 Firmware RCE Vulnerability

CVE-2025-41266 Overview

CVE-2025-41266 is an OS Command Injection vulnerability [CWE-78] in the Administration WebUI of the Waterfall WF-500 TX Host. Nozomi Networks Labs identified the flaw in firmware version 7.9.1.0 R2502171040. The vulnerability allows remote authenticated attackers to execute arbitrary operating system commands on the WF-500 TX Host. Successful exploitation compromises confidentiality, integrity, and availability of the affected industrial cybersecurity appliance.

Critical Impact

Authenticated attackers can execute arbitrary OS commands on a unidirectional security gateway used to protect operational technology environments.

Affected Products

• Waterfall Security WF-500 TX Host firmware version 7.9.1.0 R2502171040
• Waterfall Security WF-500 hardware appliance
• Administration WebUI component

Discovery Timeline

• Vulnerability discovered and reported by Nozomi Networks Labs
• 2026-05-29 - CVE-2025-41266 published to NVD
• 2026-06-01 - Last updated in NVD database

Technical Details for CVE-2025-41266

Vulnerability Analysis

The vulnerability resides in the Administration WebUI of the Waterfall WF-500 TX Host. The WebUI fails to properly neutralize special characters supplied in user-controllable input before passing that input to an underlying operating system shell. Attackers who supply crafted parameters can append or substitute shell metacharacters and execute arbitrary commands in the context of the WebUI process.

The WF-500 functions as a unidirectional security gateway separating operational technology networks from external systems. Code execution on the TX Host enables attackers to manipulate the appliance that enforces network segmentation. This category of issue is classified as [CWE-78]: Improper Neutralization of Special Elements used in an OS Command.

Root Cause

The Administration WebUI accepts attacker-supplied input and concatenates it into an operating system command string without adequate sanitization or use of safe APIs. The application does not validate input against an allowlist or escape shell metacharacters such as ;, |, &, $(), or backticks before invocation. Authenticated users with WebUI access can therefore inject command fragments interpreted by the host shell.

Attack Vector

Exploitation requires network reachability to the Administration WebUI and valid authentication credentials with sufficient privileges. An attacker authenticates to the WebUI, identifies a vulnerable parameter, and submits a request containing shell metacharacters followed by the desired command. The injected payload executes on the WF-500 TX Host. No user interaction is required beyond the attacker's own authenticated session.

No public proof-of-concept code or in-the-wild exploitation has been reported. See the Nozomi Networks Vulnerability Advisory for additional technical context.

Detection Methods for CVE-2025-41266

Indicators of Compromise

• Unexpected child processes spawned by the Administration WebUI service on the WF-500 TX Host
• WebUI access logs containing shell metacharacters such as ;, |, &, $(, or backticks in request parameters
• Outbound network connections from the WF-500 appliance to unfamiliar hosts
• New or modified files in administrative directories following WebUI activity

Detection Strategies

• Inspect HTTP request bodies and query strings sent to the WF-500 Administration WebUI for command-injection payloads
• Correlate authenticated WebUI sessions with subsequent process execution events on the appliance
• Alert on use of administrative credentials from atypical source IP addresses or outside change windows

Monitoring Recommendations

• Forward WF-500 Administration WebUI logs and authentication events to a centralized SIEM for retention and correlation
• Monitor north-south traffic to the management interface and restrict it to a dedicated administration network
• Track configuration changes on the WF-500 and compare against approved change tickets

How to Mitigate CVE-2025-41266

Immediate Actions Required

• Restrict network access to the WF-500 Administration WebUI to a hardened management subnet and trusted administrative workstations
• Rotate all WF-500 administrative credentials and enforce strong, unique passwords
• Review WebUI access logs for evidence of suspicious authenticated activity since the vulnerable firmware was installed
• Apply vendor updates as soon as Waterfall Security publishes fixed firmware

Patch Information

Consult the Nozomi Networks Vulnerability Advisory and Waterfall Security support channels for fixed firmware versions and remediation guidance. Operators of WF-500 appliances running 7.9.1.0 R2502171040 should contact Waterfall Security directly to obtain the patched release.

Workarounds

• Place the Administration WebUI behind a jump host or VPN that enforces multi-factor authentication
• Limit administrative role assignment to the minimum number of personnel required for operations
• Disable or block the WebUI interface when active administration is not in progress, where operationally feasible

# Example: restrict Administration WebUI access to a management subnet
iptables -A INPUT -p tcp --dport 443 -s 10.10.50.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP