CVE-2025-40892 is a Stored Cross-Site Scripting (XSS) vulnerability classified under CWE-79, affecting Nozomi Networks Guardian, a product widely used for industrial cybersecurity and operational technology (OT) network monitoring. The vulnerability exists in the Reports functionality due to improper neutralization of input during web page generation. Specifically, an authenticated user with report creation privileges can craft a malicious report containing embedded JavaScript payloads. Alternatively, an attacker can socially engineer a victim to import a malicious report template. When the victim views or imports this report, the malicious script executes within the victim’s browser context, leveraging the victim’s session and privileges. This execution can lead to unauthorized actions such as modifying application data, disrupting the availability of the application, and accessing sensitive information that should be limited. The vulnerability requires the attacker to have some level of authenticated access (report privileges) and relies on user interaction (viewing or importing the malicious report). The CVSS v4.0 score is 7.1 (high), reflecting network attack vector, low attack complexity, no privileges required beyond report privileges, and partial user interaction. The scope is limited to the application context but can impact confidentiality, integrity, and availability of the system. No patches or exploits are currently reported, but the risk remains significant due to the critical nature of Nozomi Guardian in OT environments.

For European organizations, the impact of this vulnerability can be substantial, especially those operating critical infrastructure such as energy, manufacturing, transportation, and utilities where Nozomi Networks Guardian is deployed for OT network visibility and security. Successful exploitation could allow attackers to manipulate monitoring data, disrupt operational continuity, or exfiltrate sensitive information about industrial processes. This could lead to operational downtime, safety incidents, regulatory non-compliance, and reputational damage. Given the increasing targeting of European critical infrastructure by cyber adversaries, this vulnerability could be leveraged in multi-stage attacks to gain deeper access or cause physical disruptions. The requirement for authenticated access somewhat limits the attack surface but does not eliminate risk, as insider threats or compromised credentials could facilitate exploitation. The need for user interaction (viewing/importing reports) means social engineering or phishing could be used to trigger the attack. Overall, the vulnerability poses a high risk to the confidentiality, integrity, and availability of critical OT systems in Europe.

1. Implement strict access controls and least privilege principles to limit report creation privileges only to trusted and trained personnel. 2. Conduct user awareness training to reduce the risk of social engineering attacks that could lead to importing malicious report templates. 3. Monitor and audit report creation and import activities to detect anomalous or unauthorized report templates. 4. Employ Content Security Policy (CSP) headers and other browser security mechanisms to reduce the impact of XSS attacks. 5. Segregate OT network management interfaces from general IT networks and restrict browser access to the Guardian web interface. 6. Regularly update and patch Nozomi Networks Guardian as vendor patches become available. 7. Use multi-factor authentication (MFA) to reduce the risk of credential compromise leading to unauthorized report creation. 8. Consider implementing web application firewalls (WAF) with custom rules to detect and block malicious payloads in report inputs. 9. Validate and sanitize all inputs on the server side as an additional layer of defense until a patch is released. 10. Establish incident response procedures specifically addressing potential XSS exploitation scenarios in OT environments.