CVE-2025-6750 is a heap-based buffer overflow vulnerability identified in version 1.14.6 of the HDF5 library, specifically within the function H5O__mtime_new_encode located in the source file src/H5Omtime.c. HDF5 is a widely used data model, library, and file format for storing and managing large amounts of data, commonly employed in scientific computing, engineering, and data-intensive applications. The vulnerability arises from improper handling of memory allocation or bounds checking during the encoding of modification time metadata, which leads to a heap buffer overflow condition. Exploitation requires local access with low privileges (local attack vector with low privileges) and does not require user interaction or elevated privileges. The vulnerability has been publicly disclosed, and although no known exploits are currently observed in the wild, the availability of proof-of-concept code could facilitate exploitation attempts. The CVSS v4.0 base score is 4.8, indicating a medium severity level. The attack complexity is low, and no authentication or user interaction is required, but the attack vector is local, limiting remote exploitation. The impact primarily affects the confidentiality and integrity of the system, as a successful overflow could lead to arbitrary code execution or application crashes, potentially allowing privilege escalation or data corruption within affected applications using HDF5 1.14.6. No patches or mitigations are explicitly linked in the provided data, emphasizing the need for users to monitor vendor advisories and update accordingly once fixes are available.

For European organizations, the impact of this vulnerability depends on the extent to which HDF5 1.14.6 is used within their environments. Sectors such as research institutions, universities, scientific computing centers, and industries relying on data analytics and large-scale data storage (e.g., aerospace, automotive, pharmaceuticals) are most at risk. Exploitation could lead to local privilege escalation or arbitrary code execution, undermining system integrity and potentially leading to data breaches or disruption of critical research and operational workflows. Given the local attack vector, insider threats or compromised user accounts pose the greatest risk. The medium severity rating suggests that while the vulnerability is not trivial, it does not present an immediate critical threat to availability or confidentiality at scale. However, the presence of publicly disclosed exploit code increases the urgency for mitigation to prevent targeted attacks, especially in environments where HDF5 is integral to data processing pipelines.

European organizations should implement the following specific mitigation measures: 1) Inventory and identify all systems and applications using HDF5 version 1.14.6 to assess exposure. 2) Restrict local access to systems running vulnerable HDF5 versions by enforcing strict access controls and monitoring for unauthorized local logins. 3) Apply principle of least privilege to limit user permissions, reducing the risk of exploitation by low-privilege users. 4) Monitor security advisories from the HDF Group and related vendors for patches or updated versions addressing CVE-2025-6750 and plan prompt deployment once available. 5) Employ runtime protection mechanisms such as heap memory protection, address space layout randomization (ASLR), and control flow integrity (CFI) to mitigate exploitation impact. 6) Conduct regular security audits and code reviews for applications integrating HDF5 to detect and remediate unsafe usage patterns. 7) Implement endpoint detection and response (EDR) solutions to identify anomalous behaviors indicative of exploitation attempts. These targeted actions go beyond generic advice by focusing on local access control, privilege management, and proactive monitoring tailored to the nature of this vulnerability.