CVE-2025-54492 is a critical stack-based buffer overflow vulnerability identified in The Biosig Project's libbiosig library, specifically affecting versions 3.9.0 and the current master branch (commit 35a819fa). The vulnerability arises in the MFER file parsing functionality, which is used to process electrophysiological data formats. The flaw occurs in the biosig.c source file at line 9141, within the code handling tag 67 (0x43), which corresponds to 'Sample skew' data. Here, an integer variable 'skew' is declared on the stack, and the function ifread() reads data into it based on a length parameter 'len'. Due to improper bounds checking, the read operation can overflow the stack memory adjacent to 'skew', leading to a stack-based buffer overflow. This overflow can be triggered by a specially crafted MFER file, allowing an attacker to execute arbitrary code without requiring any privileges or user interaction. The vulnerability has a CVSS v3.1 score of 9.8, reflecting its critical severity with network attack vector, low attack complexity, no privileges required, no user interaction, and high impact on confidentiality, integrity, and availability. Although no public exploits are currently known, the nature of the vulnerability and its ease of exploitation make it a significant threat. The Biosig library is commonly used in biomedical and neurophysiological data processing applications, which may be integrated into medical devices, research systems, or clinical software. Exploitation could lead to full system compromise, data theft, or disruption of critical medical data processing workflows.

For European organizations, especially those involved in healthcare, biomedical research, and clinical diagnostics, this vulnerability poses a substantial risk. Many European hospitals, research institutions, and medical device manufacturers utilize software that depends on libbiosig for processing electrophysiological data. Successful exploitation could allow attackers to execute arbitrary code on systems handling sensitive patient data, potentially leading to data breaches, manipulation of medical records, or disruption of diagnostic processes. This could undermine patient safety, violate GDPR data protection regulations, and result in significant reputational and financial damage. Additionally, compromised systems could be leveraged as entry points for broader network intrusions within healthcare infrastructures. The criticality of the vulnerability combined with the sensitive nature of affected systems elevates the threat level for European healthcare and research sectors.

To mitigate this vulnerability effectively, European organizations should: 1) Immediately identify all systems and applications utilizing libbiosig versions 3.9.0 or the affected master branch. 2) Apply patches or updates from The Biosig Project as soon as they become available; if no official patch exists yet, consider temporarily disabling MFER file parsing or restricting the processing of untrusted MFER files. 3) Implement strict input validation and sandboxing around components that handle MFER files to contain potential exploitation attempts. 4) Employ network segmentation and access controls to limit exposure of vulnerable systems, especially those connected to external networks. 5) Monitor logs and network traffic for anomalous activity indicative of exploitation attempts, such as unexpected file uploads or execution of unknown processes. 6) Conduct security awareness training for staff handling biomedical data to recognize and report suspicious files. 7) Collaborate with medical device vendors and software providers to ensure timely updates and coordinated vulnerability management. These measures go beyond generic advice by focusing on the specific context of libbiosig usage and the sensitive environments in which it operates.