CVE-2019-25386 in Express
Summary
by MITRE • 02/16/2026
Smoothwall Express 3.1-SP4-polar-x86_64-update9 contains multiple reflected cross-site scripting vulnerabilities in the dmzholes.cgi script that allow attackers to inject malicious scripts through unvalidated parameters. Attackers can submit POST requests with script payloads in the SRC_IP, DEST_IP, or COMMENT parameters to execute arbitrary JavaScript in users' browsers.
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Analysis
by VulDB Data Team • 02/18/2026
The vulnerability identified as CVE-2019-25386 affects Smoothwall Express version 3.1-SP4-polar-x86_64-update9, a widely used network security appliance designed for small to medium enterprises. This particular vulnerability manifests as multiple reflected cross-site scripting flaws within the dmzholes.cgi web interface script, representing a critical security weakness that directly impacts the integrity and confidentiality of user sessions. The affected system operates as a firewall and network security gateway, making it a prime target for attackers seeking to compromise network boundaries and user devices.
The technical flaw stems from inadequate input validation within the dmzholes.cgi script, specifically in how it processes parameters submitted through POST requests. When attackers exploit this vulnerability, they can inject malicious JavaScript code into the SRC_IP, DEST_IP, or COMMENT parameters, which are then reflected back to users' browsers without proper sanitization. This reflected XSS vulnerability operates through the standard HTTP POST method, where malicious payloads are submitted directly to the vulnerable script endpoint, bypassing normal input validation mechanisms that should sanitize user-supplied data before processing or displaying it within web responses.
The operational impact of this vulnerability extends beyond simple script injection, as it enables attackers to execute arbitrary JavaScript code within the context of authenticated users' browsers. This creates a significant risk for network administrators and users who interact with the Smoothwall management interface, potentially allowing attackers to steal session cookies, perform unauthorized actions on behalf of users, or redirect victims to malicious websites. The vulnerability affects all users who have access to the affected web interface, making it particularly dangerous in environments where multiple administrators or users interact with the security appliance.
Security practitioners should note that this vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications, and demonstrates characteristics consistent with the attack patterns documented in the MITRE ATT&CK framework under the T1059.007 technique for command and scripting interpreter. The attack vector requires minimal privileges to exploit, as it only requires access to the web interface, making it accessible to both internal and external threat actors who can potentially gain unauthorized access to network security controls.
Mitigation strategies should prioritize immediate patching of the affected Smoothwall Express version, as no reliable workarounds exist for this vulnerability. Organizations should implement network segmentation to limit access to the vulnerable web interface, restrict administrative access through strong authentication mechanisms, and deploy web application firewalls to detect and block malicious payloads. Additionally, regular security assessments should include testing for similar reflected XSS vulnerabilities in other web applications and scripts within the network infrastructure, particularly those handling user input through HTTP methods. The vulnerability highlights the critical importance of input validation and output encoding in web applications, as recommended by OWASP security best practices and the Secure Coding guidelines established by various industry standards organizations.