CVE-2025-2926 is a medium severity vulnerability identified in the HDF5 library versions up to 1.14.6. The flaw exists in the function H5O__cache_chk_serialize within the source file src/H5Ocache.c. Specifically, the vulnerability is a NULL pointer dereference caused by improper handling of certain conditions during the serialization of object cache checks. When triggered, this leads to a crash of the application using the HDF5 library, resulting in a denial of service (DoS) condition. The vulnerability requires local access with at least low privileges (PR:L) and does not require user interaction (UI:N). The attack vector is local (AV:L), meaning an attacker must have the ability to execute code or commands on the affected system. The CVSS 4.0 base score is 4.8, reflecting a medium severity level. The vulnerability does not impact confidentiality, integrity, or availability beyond causing a DoS. No known exploits are currently reported in the wild, but proof-of-concept code has been disclosed publicly. The vulnerability is exploitable without authentication but requires local access, limiting its remote exploitation potential. The HDF5 library is widely used in scientific computing, data analysis, and engineering applications for managing large and complex data sets in hierarchical data formats. Systems that rely on HDF5 for data storage or processing could experience application crashes or service interruptions if this vulnerability is exploited. Since the flaw is a NULL pointer dereference, it is unlikely to lead to arbitrary code execution or privilege escalation but can disrupt availability of critical data processing workflows.

For European organizations, the impact of CVE-2025-2926 primarily concerns availability disruptions in environments utilizing the HDF5 library. This includes research institutions, universities, scientific computing centers, and industries such as aerospace, automotive, pharmaceuticals, and energy sectors where large-scale data analysis and simulations are common. A successful local attack could cause application crashes, interrupting data processing pipelines and potentially delaying critical research or operational activities. Although the vulnerability does not directly compromise data confidentiality or integrity, the denial of service could have cascading effects on dependent systems and workflows. Organizations relying on automated data processing or real-time analytics may face operational downtime, impacting productivity and decision-making. Given the local attack vector, insider threats or compromised internal systems pose the greatest risk. The absence of known exploits in the wild reduces immediate threat levels, but public disclosure of the exploit code increases the risk of opportunistic attacks. European organizations with stringent uptime requirements and critical scientific workloads should prioritize addressing this vulnerability to maintain operational resilience.

To mitigate CVE-2025-2926, European organizations should: 1) Upgrade the HDF5 library to a patched version beyond 1.14.6 once available from the official maintainers, as no patch links are currently provided. 2) Restrict local access to systems running HDF5-dependent applications by enforcing strict access controls and monitoring for unauthorized local user activity. 3) Employ application-level sandboxing or containerization to isolate HDF5 processes and limit the impact of potential crashes. 4) Implement robust logging and alerting mechanisms to detect abnormal application terminations indicative of exploitation attempts. 5) Conduct internal audits to identify all systems and applications utilizing HDF5 and prioritize patching or mitigation efforts accordingly. 6) Educate system administrators and users about the risks of local exploitation and the importance of maintaining least privilege principles. 7) Where possible, implement redundancy and failover mechanisms for critical data processing workflows to minimize downtime from potential DoS events. These steps go beyond generic advice by focusing on access control, detection, and operational continuity tailored to the nature of this vulnerability.