CVE-2019-25422: Comodo Dome Firewall XSS Vulnerability

CVE-2019-25422 Overview

CVE-2019-25422 is a cross-site scripting (XSS) vulnerability [CWE-79] affecting Comodo Dome Firewall 2.7.0. The flaw resides in the vpnfw endpoint, which fails to sanitize user input submitted through POST requests. Attackers can inject JavaScript payloads via the target parameter to achieve reflected XSS, or via the remark parameter to achieve stored XSS. Successful exploitation executes arbitrary script code in the browser of an authenticated administrator viewing the affected page.

Critical Impact
Stored XSS in an administrative firewall interface enables session hijacking, credential theft, and unauthorized configuration changes against perimeter security infrastructure.

Affected Products

Comodo Dome Firewall 2.7.0
Comodo Dome Firewall (all builds exposing the vpnfw endpoint)
Deployments using the affected administrative web interface

Discovery Timeline

2026-02-19 - CVE-2019-25422 published to NVD
2026-02-20 - Last updated in NVD database

Technical Details for CVE-2019-25422

Vulnerability Analysis

The vulnerability exists in the vpnfw endpoint of the Comodo Dome Firewall administrative interface. The endpoint accepts POST parameters without applying output encoding or input sanitization before rendering values in the HTML response. Attackers can craft a POST request containing a JavaScript payload in the target parameter to produce reflected XSS. The same endpoint persists attacker-controlled content supplied through the remark parameter, enabling stored XSS that executes whenever an administrator loads the affected view.

Because the vulnerable endpoint sits within an authenticated administrative panel, successful exploitation typically requires luring an administrator into clicking a crafted link or viewing attacker-influenced configuration data. The impact extends beyond browser-level compromise: administrative XSS on a firewall appliance can be used to pivot into firewall configuration changes, including rule modifications and VPN settings.

Root Cause

The root cause is improper neutralization of input during web page generation [CWE-79]. The vpnfw handler concatenates request parameters into HTML output without context-aware escaping, and it persists the remark field without sanitization, allowing script content to survive across sessions.

Attack Vector

The attack vector is network-based with user interaction required. For reflected XSS, an attacker delivers a crafted link or auto-submitting form that issues a POST to the vpnfw endpoint with a malicious target value. For stored XSS, the attacker submits a script payload via the remark parameter, which executes when an administrator subsequently views the stored entry. Refer to the VulnCheck Comodo Dome Advisory and Exploit-DB #46408 for technical details.

Detection Methods for CVE-2019-25422

Indicators of Compromise

POST requests to the vpnfw endpoint containing <script>, onerror=, onload=, or URL-encoded JavaScript in the target or remark parameters
Unexpected outbound requests from administrator browsers to attacker-controlled domains shortly after accessing the firewall console
Firewall configuration changes, new VPN rules, or account modifications not tied to legitimate administrator activity

Detection Strategies

Inspect web server and reverse-proxy access logs for POST requests to vpnfw containing HTML or JavaScript metacharacters in parameter values
Deploy web application firewall (WAF) signatures that flag script tags, event handlers, and encoded payloads targeting the administrative interface
Correlate administrator session activity with anomalous configuration changes to identify post-exploitation actions

Monitoring Recommendations

Centralize Comodo Dome Firewall access and audit logs in a SIEM and alert on parameter values containing scripting syntax
Monitor administrator browser endpoints for unusual outbound connections initiated from firewall management sessions
Track changes to stored remark fields and review them for non-printable or script content during routine configuration audits

How to Mitigate CVE-2019-25422

Immediate Actions Required

Restrict access to the Comodo Dome Firewall management interface to a dedicated administrative network or VPN, blocking general user network access
Require administrators to use isolated browser profiles or jump hosts when managing the appliance to reduce session theft impact
Audit the vpnfw configuration for existing remark entries containing HTML or script content and remove malicious values

Patch Information

No vendor advisory or fixed version is referenced in the available CVE data. Operators should contact Comodo support to confirm whether a maintained release addresses the vpnfw XSS issue and apply any available updates. Refer to the Comodo Firewall Overview for product support channels.

Workarounds

Place the administrative interface behind a reverse proxy or WAF that strips or encodes HTML metacharacters in POST parameters to vpnfw
Enforce strict Content Security Policy (CSP) headers on the management interface to limit inline script execution
Disable or restrict use of the affected VPN firewall configuration page to a minimal set of trusted administrators until a patched version is deployed

bash

# Configuration example: WAF rule (ModSecurity) to block script payloads on vpnfw
SecRule REQUEST_URI "@contains /vpnfw" \
    "phase:2,chain,deny,status:403,id:1002542,\
     msg:'Possible XSS attempt against Comodo Dome vpnfw endpoint'"
  SecRule ARGS:target|ARGS:remark "@rx (?i)(<script|onerror=|onload=|javascript:)" \
    "t:none,t:urlDecodeUni"