CVE-2025-48988 is a high-severity vulnerability identified in the Apache Software Foundation's Apache Tomcat server, affecting multiple versions including 11.0.0-M1 through 11.0.7, 10.1.0-M1 through 10.1.41, 9.0.0.M1 through 9.0.105, and older EOL versions such as 8.5.0 through 8.5.100. The vulnerability is classified under CWE-770, which pertains to the allocation of resources without limits or throttling. This means that the affected versions of Apache Tomcat do not properly restrict the amount of resources (such as memory, threads, or file handles) that can be allocated in response to client requests. An attacker can exploit this flaw remotely without authentication or user interaction, by sending crafted requests that cause the server to allocate excessive resources. This leads to resource exhaustion, resulting in denial of service (DoS) conditions where legitimate users cannot access the service. The CVSS v3.1 base score is 7.5, reflecting a high severity due to network attack vector, low attack complexity, no privileges required, no user interaction, and an impact limited to availability (no confidentiality or integrity impact). The issue has been fixed in Apache Tomcat versions 11.0.8, 10.1.42, and 9.0.106, and users are strongly advised to upgrade to these or later versions to mitigate the risk. No known exploits are currently reported in the wild, but the nature of the vulnerability makes it a likely target for denial of service attacks once weaponized.

For European organizations, this vulnerability poses a significant risk to the availability of web applications and services hosted on Apache Tomcat servers. Apache Tomcat is widely used across Europe in both public and private sectors, including government portals, financial institutions, healthcare systems, and critical infrastructure services. A successful exploitation could lead to service outages, disrupting business operations, customer access, and potentially causing financial losses and reputational damage. The lack of required authentication and user interaction lowers the barrier for attackers, increasing the likelihood of automated or opportunistic attacks. Additionally, organizations relying on legacy or EOL versions of Tomcat are particularly vulnerable, as these versions may not receive security updates promptly. The availability impact can also affect compliance with European regulations such as GDPR, where service continuity and data protection are critical. Furthermore, denial of service attacks can be used as a smokescreen for other malicious activities, compounding the risk.

European organizations should prioritize upgrading Apache Tomcat to the fixed versions 11.0.8, 10.1.42, or 9.0.106 as soon as possible. For environments where immediate upgrade is not feasible, implementing resource limiting and throttling at the network or application layer can help mitigate risk. This includes configuring reverse proxies or web application firewalls (WAFs) to detect and block abnormal request patterns that could lead to resource exhaustion. Monitoring server resource usage and setting alerts for unusual spikes can provide early warning signs of exploitation attempts. Additionally, organizations should audit their Tomcat deployments to identify and decommission unsupported or EOL versions. Network segmentation and rate limiting can further reduce exposure. Regular vulnerability scanning and penetration testing should include checks for this vulnerability. Finally, maintaining an incident response plan that includes DoS scenarios will help minimize downtime and recovery time in case of an attack.