CVE-2025-54492 is a stack-based buffer overflow vulnerability identified in The Biosig Project's libbiosig library, specifically in the MFER file parsing code. The vulnerability arises in the function handling tag 67 (0x43), which corresponds to 'Sample skew' data. The code improperly reads data into a newly defined integer variable 'skew' using the ifread function without adequate bounds checking on the length parameter 'len'. Instead of overflowing a buffer, the overflow corrupts the stack location of 'skew', leading to a stack overflow condition with relatively small input sizes. This flaw enables an attacker to craft a malicious MFER file that, when processed by libbiosig, can cause arbitrary code execution. The vulnerability affects version 3.9.0 and the current master branch (commit 35a819fa). The CVSS 3.1 base score is 9.8, indicating critical severity with network attack vector, no privileges required, no user interaction, and full impact on confidentiality, integrity, and availability. No patches or exploits are currently publicly available, but the vulnerability's nature makes it a prime target for exploitation in environments processing biosignal data. The Biosig Project is a specialized open-source library used in biomedical signal processing, so affected systems are likely in healthcare, research, and biometric authentication domains.

The impact of CVE-2025-54492 on European organizations is significant, especially for those in healthcare, biomedical research, and biometric authentication sectors that utilize The Biosig Project's libbiosig library. Exploitation can lead to arbitrary code execution, allowing attackers to compromise system confidentiality, integrity, and availability. This could result in unauthorized access to sensitive patient data, manipulation of biomedical signals, disruption of critical healthcare services, and potential cascading effects on connected systems. Given the critical nature of healthcare infrastructure in Europe and the increasing reliance on digital biomedical tools, this vulnerability could undermine trust in medical devices and research data integrity. Additionally, organizations involved in biometric authentication may face identity theft or unauthorized access risks. The lack of required authentication or user interaction lowers the barrier for attackers, increasing the likelihood of exploitation once a public exploit emerges. The absence of known exploits currently provides a window for proactive mitigation, but the critical CVSS score demands urgent attention.

To mitigate CVE-2025-54492, European organizations should immediately audit their software stacks to identify any usage of libbiosig version 3.9.0 or the affected master branch. Since no official patches are currently available, organizations should consider the following specific actions: 1) Temporarily disable or isolate components that process MFER files using libbiosig until a patch is released. 2) Implement strict input validation and sandboxing around any functionality that parses MFER files to contain potential exploitation attempts. 3) Monitor network and system logs for anomalous activity related to MFER file processing, including unexpected crashes or memory errors. 4) Engage with The Biosig Project community or maintainers to obtain or contribute patches addressing the vulnerability. 5) For developers, review and refactor the parsing code to include proper bounds checking on the 'len' parameter and avoid stack variable overflow. 6) Employ runtime protections such as stack canaries, DEP (Data Execution Prevention), and ASLR (Address Space Layout Randomization) to reduce exploitation success. 7) Educate staff about the risks of processing untrusted biosignal files and enforce strict file provenance policies. These targeted measures go beyond generic advice by focusing on the specific vulnerable code path and operational context.