CVE-2025-40831 is a vulnerability identified in Siemens SINEC Security Monitor, a network security monitoring tool widely used in industrial and critical infrastructure environments. The flaw stems from improper input validation (CWE-20) of a date parameter used in the report generation feature. Specifically, the application fails to properly validate or sanitize the date input, which can be manipulated by an authenticated user with low privileges. Exploiting this vulnerability allows the attacker to trigger a denial of service condition, effectively disrupting the report generation process. This could hinder security monitoring and incident response activities that rely on timely and accurate reports. The vulnerability affects all versions prior to 4.10.0. The CVSS v3.1 base score is 6.5, indicating a medium severity level. The attack vector is network-based (AV:N), with low attack complexity (AC:L), requiring privileges (PR:L) but no user interaction (UI:N). The impact is limited to availability (A:H) with no confidentiality or integrity impact. No public exploits have been reported to date. Siemens has not yet published a patch, but organizations are advised to monitor for updates. The vulnerability’s root cause is insufficient input validation, a common software weakness that can lead to various issues including denial of service. Given the critical role of SINEC Security Monitor in industrial network security, this vulnerability could disrupt operational monitoring and delay detection of other threats.

For European organizations, especially those in critical infrastructure sectors such as energy, manufacturing, and transportation, this vulnerability poses a risk to operational continuity. Disruption of report generation can delay detection and response to security incidents, increasing the risk of undetected attacks or operational failures. Although the vulnerability does not directly compromise confidentiality or integrity, the denial of service impact on availability can degrade security posture and compliance with regulatory requirements such as NIS2. Organizations relying on Siemens SINEC Security Monitor for network visibility and security analytics may experience reduced situational awareness. This could be particularly impactful in environments where timely reporting is essential for operational safety and regulatory audits. The requirement for authenticated access limits the attack surface but does not eliminate risk, as insider threats or compromised low-privilege accounts could exploit this flaw. The absence of known exploits reduces immediate risk but does not preclude future exploitation attempts. Overall, the vulnerability could lead to operational disruptions and increased exposure to other cyber threats if not addressed promptly.

1. Apply Siemens-provided patches or updates as soon as they become available for SINEC Security Monitor versions prior to 4.10.0. 2. Restrict access to the report generation functionality to only trusted and necessary personnel to minimize the risk of exploitation by low-privilege users. 3. Implement strict authentication and authorization controls, including multi-factor authentication, to reduce the likelihood of account compromise. 4. Monitor logs and alerts for unusual or failed report generation attempts that may indicate exploitation attempts. 5. Consider deploying network segmentation to isolate the SINEC Security Monitor system from less trusted network zones. 6. Conduct regular security audits and vulnerability assessments focusing on input validation and access controls within industrial control systems. 7. Educate users about the risks of improper input handling and encourage reporting of anomalies. 8. If patching is delayed, implement compensating controls such as input filtering or proxy validation where feasible to sanitize inputs before they reach the application.