CVE-2025-54484 is a critical stack-based buffer overflow vulnerability identified in The Biosig Project's libbiosig library, specifically affecting versions 3.9.0 and the Master Branch (commit 35a819fa). The vulnerability arises in the MFER file parsing functionality, which is used to process electrophysiological data formats. The flaw is located in biosig.c at line 8779, where the code handles a specific tag (tag==6) representing the "number of sequences" field. The vulnerability occurs because the code does not properly validate the length of the input data before reading it into a fixed-size buffer on the stack. If the length exceeds the expected size (greater than 4 bytes), it triggers a buffer overflow condition. This unchecked buffer operation allows an attacker to craft a malicious MFER file that, when parsed by libbiosig, can lead to arbitrary code execution. The CVSS v3.1 base score is 9.8, indicating a critical severity with network attack vector, no privileges required, no user interaction, and impacts on confidentiality, integrity, and availability. Although no known exploits are currently reported in the wild, the ease of exploitation and the critical impact make this a high-risk vulnerability. The vulnerability affects any application or system that uses libbiosig for processing MFER files, potentially including medical, research, or bioinformatics software that relies on electrophysiological data analysis.

For European organizations, the impact of CVE-2025-54484 can be significant, especially in sectors such as healthcare, biomedical research, and academic institutions that utilize electrophysiological data processing tools incorporating libbiosig. Exploitation could lead to arbitrary code execution, allowing attackers to compromise sensitive patient data, disrupt critical research workflows, or gain persistent access to internal networks. Given the critical nature of the vulnerability, it could also be leveraged as an initial attack vector for broader network infiltration or ransomware deployment. The confidentiality, integrity, and availability of sensitive biomedical data are at risk, potentially violating GDPR regulations and leading to legal and reputational consequences. Furthermore, disruption in healthcare or research services could have downstream effects on patient care and scientific progress. The lack of required privileges and user interaction increases the threat level, as attackers can exploit the vulnerability remotely by delivering malicious MFER files through various vectors such as email attachments, file uploads, or network shares.

To mitigate this vulnerability, European organizations should take the following specific actions: 1) Immediately identify and inventory all systems and software components that use libbiosig version 3.9.0 or the affected master branch, focusing on applications handling MFER files. 2) Apply patches or updates from The Biosig Project as soon as they become available; if no official patch exists yet, consider temporary mitigations such as disabling MFER file parsing or restricting file inputs to trusted sources only. 3) Implement strict input validation and sandboxing for any process handling MFER files to contain potential exploitation attempts. 4) Employ network-level protections such as file scanning and filtering to detect and block malicious MFER files from entering the environment. 5) Monitor logs and system behavior for anomalies indicative of exploitation attempts, including unexpected process executions or memory errors related to libbiosig usage. 6) Educate relevant staff about the risks of opening untrusted electrophysiological data files and enforce policies for secure file handling. 7) Consider deploying application whitelisting and endpoint detection and response (EDR) solutions to detect and prevent exploitation activities. These measures, combined with timely patching, will reduce the risk of successful exploitation and limit potential damage.