CVE-2025-6269 is a heap-based buffer overflow vulnerability identified in the HDF5 library versions 1.14.0 through 1.14.6. The flaw exists specifically in the function H5C__reconstruct_cache_entry within the source file H5Cimage.c. This function is responsible for reconstructing cache entries, and improper handling of input data leads to a heap overflow condition. Exploitation requires local access with at least low-level privileges (PR:L), meaning an attacker must have some level of authenticated access to the system but does not require user interaction or elevated privileges. The vulnerability does not affect confidentiality, integrity, or availability to a high degree, as reflected by the CVSS 4.8 score (medium severity). The attack vector is local, and the complexity is low, but the scope and impact are limited due to the need for local access and the absence of remote exploitation capabilities. No known exploits are currently observed in the wild, but a public proof-of-concept or exploit code has been disclosed, increasing the risk of future exploitation. HDF5 is a widely used data model, library, and file format for storing and managing large scientific data sets, commonly employed in research institutions, engineering, and data-intensive industries. The vulnerability could allow an attacker to execute arbitrary code or cause a denial of service by corrupting memory, potentially leading to application crashes or unexpected behavior when processing HDF5 files.

For European organizations, the impact of this vulnerability depends largely on the extent to which HDF5 is used within their environments. Institutions involved in scientific research, engineering, aerospace, automotive, and data analytics are more likely to utilize HDF5 libraries. Exploitation could lead to local privilege escalation or denial of service conditions, disrupting critical data processing workflows. While the vulnerability requires local access, it could be leveraged by malicious insiders or attackers who have already compromised lower-privileged accounts. This could result in data corruption or system instability, impacting research integrity and operational continuity. The medium severity rating suggests that while the vulnerability is not immediately critical, it poses a tangible risk to organizations relying on HDF5 for data management. Additionally, the public disclosure of exploit details increases the urgency for timely patching to prevent potential exploitation in sensitive environments.

European organizations should prioritize updating HDF5 libraries to versions beyond 1.14.6 where this vulnerability is patched. If immediate patching is not feasible, organizations should implement strict access controls to limit local user privileges, ensuring that only trusted users have access to systems running vulnerable HDF5 versions. Employ application whitelisting and endpoint detection and response (EDR) solutions to monitor for unusual behavior indicative of exploitation attempts. Conduct thorough audits of systems using HDF5 to identify and isolate vulnerable instances. Additionally, organizations should enforce strict file integrity monitoring on HDF5-related files and logs to detect tampering or anomalous activity. For environments where HDF5 is used in multi-user or shared systems, consider sandboxing or containerizing applications to limit the blast radius of potential exploits. Finally, raise awareness among system administrators and users about the risks of local exploitation and the importance of maintaining updated software components.