CVE-2025-59328 is a vulnerability classified under CWE-502 (Deserialization of Untrusted Data) found in the Apache Software Foundation's Apache Fory library, specifically affecting version 0.5.0. The root cause is insecure deserialization, where the library processes untrusted input data without adequate validation or sanitization. An attacker can exploit this by sending a specially crafted data payload that, when deserialized, consumes an excessive amount of CPU resources. This resource exhaustion leads to Denial of Service (DoS), making the application or system unresponsive and unavailable to legitimate users. The attack vector is remote network access, with low attack complexity and no user interaction required, but it requires some level of privileges (PR:L). The vulnerability does not impact confidentiality or integrity but severely affects availability. No known exploits have been reported in the wild yet. The Apache Software Foundation has addressed this issue in Apache Fory version 0.12.2, and users are strongly advised to upgrade. Developers depending on Apache Fory should update their dependencies accordingly and release patched versions of their software to prevent exploitation.

For European organizations, this vulnerability poses a significant risk to service availability, especially for those relying on Apache Fory in critical applications or infrastructure. The DoS condition caused by CPU exhaustion can disrupt business operations, degrade user experience, and potentially cause cascading failures in dependent systems. Industries such as finance, telecommunications, government services, and healthcare, which often require high availability and resilience, could face operational interruptions. Additionally, organizations with compliance obligations around service uptime and incident response may face regulatory scrutiny if affected. The absence of confidentiality or integrity impact reduces the risk of data breaches but does not diminish the operational threat. The medium CVSS score reflects the moderate severity but emphasizes the importance of timely patching to prevent denial of service attacks that could be leveraged during broader cyber campaigns or as a distraction for other malicious activities.

To mitigate CVE-2025-59328, European organizations should: 1) Immediately upgrade all instances of Apache Fory to version 0.12.2 or later, as this version contains the fix for the insecure deserialization vulnerability. 2) Audit all internal and third-party software dependencies to identify any libraries or applications that incorporate Apache Fory 0.5.0 and coordinate with vendors or development teams to update those dependencies. 3) Implement network-level protections such as rate limiting and anomaly detection to identify and block unusually large or malformed payloads targeting deserialization endpoints. 4) Employ application-layer firewalls or runtime application self-protection (RASP) tools that can detect and prevent deserialization attacks. 5) Monitor CPU usage and application logs for signs of abnormal resource consumption that could indicate exploitation attempts. 6) Conduct security code reviews and testing focused on deserialization processes in custom applications to ensure safe handling of untrusted data. 7) Establish incident response procedures to quickly isolate and remediate affected systems in case of an attack. These steps go beyond generic advice by emphasizing dependency management, proactive monitoring, and layered defenses tailored to deserialization vulnerabilities.