CVE-2025-10240 is a Cross-site Scripting (XSS) vulnerability classified under CWE-79 that affects the Progress Software Flowmon web application versions prior to 12.5.5. The vulnerability arises from improper neutralization of user-supplied input during web page generation, allowing malicious scripts to be injected and executed in the context of an authenticated user's session. An attacker can exploit this by crafting a malicious URL and convincing a legitimate user to click it, triggering unintended actions such as session hijacking, data theft, or unauthorized commands executed with the victim's privileges. The vulnerability has a CVSS 3.1 base score of 8.8, indicating high severity, with attack vector being network accessible, no privileges required, but user interaction necessary. The impact covers confidentiality, integrity, and availability, as the attacker can potentially steal sensitive data, manipulate application behavior, or disrupt services. No public exploit code is currently known, but the risk remains significant due to the ease of exploitation once a user clicks the malicious link. Flowmon is widely used in network monitoring and security analytics, making this vulnerability particularly concerning for organizations relying on it for critical infrastructure monitoring. The vulnerability was publicly disclosed on October 9, 2025, with no patch links provided yet, emphasizing the need for immediate attention from users of affected versions.

For European organizations, the impact of this vulnerability can be severe. Flowmon is often deployed in enterprise environments for network traffic analysis and security monitoring, including critical infrastructure sectors such as energy, telecommunications, and finance. Exploitation could lead to unauthorized access to sensitive network data, manipulation of monitoring results, or disruption of network visibility, undermining incident response capabilities. Confidentiality breaches could expose internal network topologies and sensitive operational data. Integrity violations might allow attackers to inject false alerts or hide malicious activities, while availability impacts could disrupt monitoring services, delaying threat detection. Given the high CVSS score and the requirement for only user interaction, phishing campaigns targeting employees could be an effective attack vector. This risk is amplified in sectors with stringent regulatory requirements like GDPR, where data breaches can lead to significant legal and financial penalties. Therefore, European organizations must prioritize remediation to maintain operational security and compliance.

1. Upgrade Flowmon to version 12.5.5 or later as soon as the patch becomes available to address the vulnerability directly. 2. Until patching is possible, implement strict input validation and sanitization on all user-supplied data within the application to prevent script injection. 3. Deploy Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in the web application context. 4. Educate users on the risks of clicking unsolicited or suspicious links, especially those that could lead to internal applications. 5. Monitor web application logs and network traffic for unusual activity indicative of attempted exploitation, such as unexpected script execution or anomalous session behavior. 6. Employ web application firewalls (WAF) with rules tailored to detect and block XSS attack patterns targeting Flowmon interfaces. 7. Conduct regular security assessments and penetration testing focused on web application vulnerabilities to identify and remediate similar issues proactively.