CVE-2024-9823 identifies a resource exhaustion vulnerability (CWE-400) in the DosFilter component of the Eclipse Foundation's Jetty server, versions 9.0.0, 10.0.0, and 11.0.0. Jetty is a widely used Java-based HTTP server and servlet container often embedded in enterprise applications and middleware. DosFilter is intended to protect servers from denial-of-service attacks by limiting request rates. However, this vulnerability allows an unauthenticated remote attacker to bypass these protections by sending specially crafted HTTP requests in rapid succession. These requests cause the server to consume excessive memory resources, eventually triggering OutOfMemory errors that crash or severely degrade the server's availability. The vulnerability does not impact confidentiality or integrity, as it does not allow data leakage or modification. The attack vector is network-based with low attack complexity and no privileges or user interaction required, making exploitation feasible in exposed environments. Although no public exploits have been reported yet, the potential for service disruption is significant, especially for high-availability systems. The absence of patches at the time of disclosure necessitates interim mitigations such as rate limiting at upstream proxies or disabling DosFilter if feasible. Monitoring for anomalous request patterns and resource usage is also advised. This vulnerability underscores the importance of robust DoS mitigation mechanisms and timely updates in critical middleware components.

For European organizations, the primary impact of CVE-2024-9823 is on service availability. Organizations relying on Jetty for web services, APIs, or middleware may experience outages or degraded performance due to memory exhaustion caused by malicious request floods. This can disrupt business operations, customer access, and internal processes. Sectors with high dependence on continuous web service availability, such as finance, healthcare, e-government, and telecommunications, are particularly vulnerable. The vulnerability does not compromise data confidentiality or integrity, but denial-of-service conditions can indirectly affect trust and compliance with service-level agreements (SLAs). Additionally, organizations may face reputational damage and potential regulatory scrutiny if service disruptions impact critical infrastructure or public services. The ease of exploitation and lack of authentication requirements increase the risk of opportunistic attacks, especially against publicly accessible Jetty instances. European entities using older or unpatched Jetty versions should assess exposure and prioritize mitigation to maintain operational resilience.

1. Monitor vendor communications closely for official patches or updates addressing CVE-2024-9823 and apply them promptly once available. 2. In the interim, consider disabling the DosFilter component if it is not essential or if alternative DoS protections are in place. 3. Implement upstream rate limiting and traffic filtering at network edge devices or reverse proxies to restrict the volume of requests reaching Jetty servers. 4. Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious request patterns indicative of resource exhaustion attempts. 5. Enhance server resource monitoring to detect abnormal memory usage spikes and automate alerts for potential attacks. 6. Conduct regular security assessments and penetration tests focusing on DoS resilience of Jetty deployments. 7. Where feasible, deploy Jetty instances behind load balancers that can absorb or mitigate traffic spikes. 8. Review and harden application-level request handling to minimize resource consumption per request. 9. Document and rehearse incident response plans for DoS scenarios to reduce downtime. 10. Educate development and operations teams about this vulnerability and best practices for DoS mitigation in Java-based web servers.