CVE-2025-2308 is a heap-based buffer overflow vulnerability identified in version 1.14.6 of the HDF5 library, specifically within the Scale-Offset Filter component's function H5Z__scaleoffset_decompress_one_byte. HDF5 is a widely used data model, library, and file format for storing and managing large and complex data, commonly employed in scientific computing, engineering, and data analytics environments. The vulnerability arises when the decompression function improperly handles data, leading to a heap buffer overflow condition. This can cause memory corruption, potentially allowing an attacker with local access and low-level privileges to execute arbitrary code or cause a denial of service by crashing the application using the library. The attack vector requires local access with low privileges, no user interaction, and no authentication bypass, limiting remote exploitation possibilities. The vulnerability has been publicly disclosed, but no known exploits are currently observed in the wild. The vendor has announced plans to release a patch in a future update. The CVSS 4.0 score is 4.8 (medium severity), reflecting the limited attack vector and moderate impact on confidentiality, integrity, and availability. However, the critical classification mentioned in the description likely refers to the potential severity if exploited in sensitive environments. Given HDF5's role in critical data processing pipelines, exploitation could lead to significant disruption or data compromise in affected systems.

For European organizations, especially those in research institutions, universities, engineering firms, and industries relying on scientific data processing (such as aerospace, automotive, pharmaceuticals, and energy sectors), this vulnerability poses a risk of local privilege escalation or denial of service. Since HDF5 is often embedded in custom or commercial scientific software, exploitation could lead to corruption or loss of critical data, interruption of data analysis workflows, or unauthorized code execution on affected hosts. The requirement for local access reduces the risk of widespread remote attacks but raises concerns for insider threats or compromised internal systems. Organizations handling sensitive or regulated data (e.g., GDPR-protected personal data or intellectual property) could face confidentiality breaches or operational disruptions. Additionally, the absence of a patch at present necessitates proactive risk management to prevent exploitation during the vulnerability window.

European organizations should immediately identify and inventory all systems and applications using HDF5 version 1.14.6, focusing on those with the Scale-Offset Filter enabled. Until a patch is released, restrict local access to trusted users only and enforce strict access controls and monitoring on systems running vulnerable versions. Employ application whitelisting and endpoint detection and response (EDR) solutions to detect anomalous behavior indicative of exploitation attempts. Where feasible, disable or limit the use of the Scale-Offset Filter in HDF5 configurations to reduce the attack surface. Conduct thorough code reviews and testing for internally developed software that integrates HDF5 to identify potential exploit triggers. Prepare for rapid deployment of the vendor patch once available, including testing in controlled environments. Additionally, implement network segmentation to isolate critical systems and reduce insider threat risks. Regularly update and audit user privileges to minimize the number of users with local access to vulnerable systems.