CVE-2025-34246 is a SQL injection vulnerability identified in Advantech WebAccess/VPN products prior to version 1.1.5. The flaw exists in the AjaxPrevalidationController.ajaxAction() method, which processes datatable search parameters without proper sanitization or neutralization of special SQL elements. This improper input validation allows an authenticated user with low-level observer privileges to craft malicious SQL queries that are executed by the backend database. As a result, the attacker can retrieve sensitive database information, potentially including user credentials, configuration data, or other critical system information. The vulnerability does not require elevated privileges beyond observer access, nor does it require additional user interaction, making it relatively easy to exploit remotely over the network. The CVSS 4.0 base score is 5.3 (medium), reflecting the moderate impact on confidentiality and the ease of exploitation given the low privilege requirement. No public exploits have been reported yet, but the vulnerability poses a significant risk to organizations relying on this product for secure remote access and industrial control system monitoring. The lack of a patch link suggests that a fix may be pending or that users must upgrade to a newer version once available. Given the product’s use in industrial and critical infrastructure environments, exploitation could lead to unauthorized data disclosure and potential operational disruptions.

For European organizations, this vulnerability presents a risk of unauthorized disclosure of sensitive operational and configuration data stored within Advantech WebAccess/VPN databases. Such data leaks could facilitate further attacks, including privilege escalation or lateral movement within industrial control networks. Organizations in sectors such as manufacturing, energy, utilities, and transportation that use Advantech products for remote monitoring and VPN access are particularly vulnerable. Exposure of sensitive data could lead to operational downtime, regulatory non-compliance (e.g., GDPR breaches due to data exposure), reputational damage, and financial losses. The medium severity rating reflects that while the vulnerability does not allow direct system takeover or denial of service, the confidentiality impact is significant in environments where data integrity and secrecy are critical. The requirement for authenticated access limits exposure but does not eliminate risk, especially if observer accounts are widely distributed or credentials are compromised.

1. Upgrade Advantech WebAccess/VPN to version 1.1.5 or later as soon as the patch is available to ensure the vulnerability is fully remediated. 2. Restrict the number of observer-level accounts and enforce strong authentication controls to reduce the attack surface. 3. Implement strict input validation and sanitization on all user-supplied parameters, particularly those used in SQL queries, if custom integrations or legacy versions are in use. 4. Deploy Web Application Firewalls (WAFs) with rules specifically designed to detect and block SQL injection attempts targeting the AjaxPrevalidationController.ajaxAction() endpoint. 5. Conduct regular security audits and penetration testing focusing on web application vulnerabilities in industrial control system interfaces. 6. Monitor logs for unusual query patterns or access attempts by observer users that may indicate exploitation attempts. 7. Educate administrators and users about the risks of SQL injection and the importance of limiting observer privileges.