CVE-2025-66359 is a cross-site scripting (XSS) vulnerability identified in Logpoint SIEM products prior to version 7.7.0. The root cause is insufficient input validation and lack of output escaping in multiple components of the SIEM platform, which allows attackers to inject malicious scripts into web pages generated by the system. This vulnerability is classified under CWE-79, indicating improper neutralization of input during web page generation. The CVSS v3.1 base score is 8.5, reflecting a high severity level. The vector string (AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H) indicates that the attack can be performed remotely over the network, requires high attack complexity, low privileges, no user interaction, and results in a scope change with high impact on confidentiality, integrity, and availability. Exploiting this vulnerability could allow an attacker to execute arbitrary scripts in the context of the SIEM web interface, potentially leading to theft of sensitive security data, manipulation of logs, or disruption of monitoring capabilities. Although no known exploits have been reported in the wild yet, the vulnerability poses a significant risk due to the critical role of SIEM systems in organizational security. The lack of patch links suggests that a fix may not yet be publicly available, emphasizing the need for vigilance and interim mitigations. The vulnerability affects all versions before 7.7.0, but the exact affected versions are not detailed beyond this. Given the nature of SIEM systems, attackers could leverage this vulnerability to gain deeper access or cover tracks within monitored environments.

For European organizations, the impact of CVE-2025-66359 is substantial. SIEM systems like Logpoint are central to security operations, aggregating and analyzing logs from across the network to detect threats. A successful XSS attack could allow adversaries to execute malicious scripts within the SIEM interface, potentially leading to unauthorized access to sensitive security data, manipulation or deletion of logs, and disruption of incident detection and response processes. This undermines the integrity and reliability of security monitoring, increasing the risk of undetected breaches. Confidentiality is at risk as attackers could exfiltrate sensitive information displayed or stored within the SIEM. Availability could also be impacted if the system is destabilized or manipulated to ignore certain alerts. Given the high reliance on SIEM tools in sectors such as finance, energy, healthcare, and government across Europe, exploitation could have cascading effects on critical infrastructure and regulatory compliance. The high attack complexity and requirement for low privileges somewhat limit the ease of exploitation, but the absence of required user interaction increases risk in automated or unattended environments. Organizations may face regulatory repercussions under GDPR if security monitoring is compromised, especially if personal data is involved.

Immediate mitigation should focus on upgrading Logpoint SIEM installations to version 7.7.0 or later once the patch is released. Until then, organizations should implement strict input validation and output encoding in any custom dashboards, plugins, or integrations with the SIEM to reduce injection risks. Network segmentation and access controls should limit exposure of the SIEM web interface to trusted administrators only. Employ web application firewalls (WAFs) with rules targeting XSS payloads to provide an additional layer of defense. Monitor SIEM logs and web server access logs for unusual or suspicious activity indicative of attempted exploitation. Conduct regular security assessments and penetration tests focusing on the SIEM environment. Educate administrators on recognizing signs of XSS attacks and ensure multi-factor authentication is enforced to reduce the risk of compromised credentials. Finally, maintain an incident response plan specifically addressing potential SIEM compromise scenarios to enable rapid containment and recovery.