CVE-2023-7318 is a cross-site scripting (XSS) vulnerability identified in Nagios XI, a widely used IT infrastructure monitoring solution. The flaw exists in the Nagios Core Command Expansion page, where user-supplied input is insufficiently validated or escaped before being incorporated into web pages. This improper neutralization of input (CWE-79) allows an attacker with low privileges to inject arbitrary JavaScript code that executes in the context of other users' browsers who access the vulnerable page. The vulnerability does not require high privileges or authentication beyond low-level access, but it does require user interaction, such as a victim visiting a crafted URL or page. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:L), user interaction required (UI:P), and low scope impact (S: I). The vulnerability impacts confidentiality and integrity by enabling potential session hijacking, credential theft, or unauthorized actions performed via the victim's browser session. No public exploits have been reported, but the presence of this vulnerability in monitoring infrastructure software poses a risk to organizations relying on Nagios XI for critical system oversight. The vulnerability was published on 30 October 2025, and Nagios XI versions prior to 2024R1.0.2 are affected. No official patches or mitigation links were provided in the data, but upgrading to the fixed version is implied. The vulnerability's medium severity reflects the balance between ease of exploitation and impact scope.

For European organizations, the impact of CVE-2023-7318 can be significant, especially for entities relying heavily on Nagios XI for monitoring critical IT infrastructure, such as energy providers, financial institutions, healthcare, and government agencies. Successful exploitation could allow attackers to execute malicious scripts in the browsers of administrators or operators, potentially leading to session hijacking, theft of sensitive monitoring data, or unauthorized commands executed within the monitoring environment. This could disrupt monitoring capabilities, delay incident detection, or facilitate lateral movement within networks. Given the vulnerability requires low privileges but user interaction, phishing or social engineering could be leveraged to trigger attacks. The impact on confidentiality and integrity is moderate, while availability impact is limited but possible if attackers manipulate monitoring data or commands. Organizations with exposed Nagios XI web interfaces or insufficient network segmentation are at higher risk. The lack of known exploits reduces immediate threat but does not eliminate risk, especially as attackers may develop exploits post-disclosure.

1. Upgrade Nagios XI to version 2024R1.0.2 or later as soon as possible to apply the official fix addressing this XSS vulnerability. 2. Implement strict input validation and output encoding on all user-supplied data within the Nagios XI web interface, particularly on the Core Command Expansion page, to prevent injection of malicious scripts. 3. Restrict access to the Nagios XI web interface using network segmentation, VPNs, or IP whitelisting to limit exposure to trusted users only. 4. Educate administrators and users about phishing and social engineering risks to reduce the likelihood of user interaction leading to exploitation. 5. Monitor web server logs and application logs for suspicious requests or unusual activity related to the vulnerable page. 6. Employ Content Security Policy (CSP) headers to mitigate the impact of potential XSS attacks by restricting the execution of unauthorized scripts. 7. Regularly review and update security configurations and conduct penetration testing focused on web application vulnerabilities within Nagios XI deployments.