CVE-2025-44824 is an incorrect authorization vulnerability (CWE-863) identified in Nagios Log Server versions before 2024R1.3.2. The flaw allows authenticated users who possess only read-only API access privileges to stop the Elasticsearch service by sending a crafted HTTP request to the endpoint /nagioslogserver/index.php/api/system/stop?subsystem=elasticsearch. Despite the API returning a message indicating failure to stop Elasticsearch ("Could not stop elasticsearch"), the service actually stops, causing a denial of service condition. This vulnerability arises from insufficient authorization checks on the API endpoint, allowing privilege escalation from read-only to disruptive actions. Elasticsearch is a critical component of Nagios Log Server, responsible for indexing and searching logs; its stoppage disrupts log collection, analysis, and alerting functions, severely impacting monitoring capabilities. The CVSS v3.1 score of 8.5 reflects the network attack vector, low attack complexity, required privileges (low), no user interaction, and a scope change with high impact on availability and integrity but no confidentiality loss. No public exploits have been reported yet, but the vulnerability’s nature makes it a prime target for attackers aiming to disrupt monitoring infrastructure. The issue was reserved in April 2025 and published in October 2025, with no patch links currently available, indicating that organizations must implement interim mitigations.

For European organizations, the impact of CVE-2025-44824 is significant, especially for those relying on Nagios Log Server for critical infrastructure monitoring, security event logging, and compliance reporting. Disruption of Elasticsearch service leads to loss of log data availability and delayed or missed alerts, which can hinder incident detection and response. This can increase the risk of undetected breaches or operational failures. Industries such as finance, energy, healthcare, and government agencies, which often use Nagios for centralized log management, may face operational downtime and regulatory compliance issues. The vulnerability could be exploited by insider threats or compromised accounts with read-only API access, making internal security controls and monitoring essential. The denial of service could also be leveraged as part of a larger attack campaign to mask malicious activities. Given the high CVSS score and the critical role of log servers in security operations, the threat poses a substantial risk to European organizations’ cybersecurity posture and operational resilience.

1. Immediately restrict API access to trusted users and systems, enforcing strict authentication and authorization controls, especially limiting read-only API users from accessing system control endpoints. 2. Implement network segmentation and firewall rules to restrict access to the Nagios Log Server API endpoints, allowing only necessary management systems. 3. Monitor API logs for suspicious or anomalous calls to the /api/system/stop endpoint or other unusual activity indicative of exploitation attempts. 4. Employ application-layer firewalls or API gateways that can enforce granular access policies and detect unauthorized commands. 5. Until an official patch is released, consider disabling or restricting the vulnerable API endpoint if feasible without disrupting operations. 6. Prepare to apply vendor patches promptly once available and verify the effectiveness of the fix in test environments before production deployment. 7. Conduct regular audits of user privileges to ensure no excessive permissions are granted, minimizing the attack surface. 8. Enhance internal monitoring and alerting to detect potential misuse of read-only credentials or unexpected service stoppages. 9. Educate administrators and security teams about this vulnerability and the importance of safeguarding API credentials.