CVE-2023-7313 is a cross-site scripting (XSS) vulnerability classified under CWE-79 that affects Nagios XI versions prior to 5.11.3. The vulnerability exists in the Bulk Modifications tool where insufficient validation or escaping of user-supplied input allows an attacker to inject malicious scripts. When a victim interacts with the crafted input, the injected script executes in their browser context, potentially enabling session hijacking, theft of credentials, or unauthorized actions within the Nagios XI web interface. The vulnerability has a CVSS 4.0 base score of 5.1, indicating medium severity. The vector metrics indicate network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:L - low privileges), and user interaction required (UI:P). The scope is limited (S: I), and the impact on confidentiality, integrity, and availability is none or low, but the risk lies in the potential misuse of user sessions or data. No known exploits have been reported in the wild, but the vulnerability's presence in a widely used IT infrastructure monitoring tool makes it a notable risk. The lack of a patch link in the provided data suggests organizations should verify with Nagios for updates or mitigations. The vulnerability highlights the importance of proper input sanitization and escaping in web applications, especially those managing critical infrastructure.

For European organizations, the impact of CVE-2023-7313 can be significant due to the role Nagios XI plays in monitoring IT infrastructure and critical systems. Successful exploitation could allow attackers to execute arbitrary scripts in the context of legitimate users, potentially leading to session hijacking, unauthorized access to monitoring data, or manipulation of monitoring configurations. This could disrupt incident detection and response, delay remediation efforts, or expose sensitive operational data. Organizations in sectors such as finance, energy, telecommunications, and government, which rely heavily on Nagios XI for infrastructure monitoring, may face increased risk of operational disruption or data breaches. The medium severity score reflects moderate risk, but the potential for lateral movement or escalation within an environment after initial compromise elevates the threat. Additionally, the requirement for user interaction and low privileges reduces the likelihood of automated exploitation but does not eliminate targeted attacks. The absence of known exploits in the wild currently lowers immediate risk but should not lead to complacency.

European organizations should immediately verify their Nagios XI version and upgrade to version 5.11.3 or later where the vulnerability is patched. In the absence of an official patch, organizations should restrict access to the Bulk Modifications tool to trusted administrators only and implement strict input validation and output encoding on all user-supplied data within Nagios XI interfaces. Deploying Content Security Policies (CSP) can help mitigate the impact of injected scripts by restricting script execution sources. Monitoring and logging user activities around the Bulk Modifications tool can help detect suspicious behavior indicative of exploitation attempts. Additionally, organizations should educate users about the risks of interacting with untrusted links or inputs within the Nagios XI environment. Network segmentation and multi-factor authentication (MFA) for Nagios XI access can further reduce the risk of exploitation. Regular vulnerability scanning and penetration testing focused on web application security should be conducted to identify similar issues proactively.