CVE-2025-54480 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 resides in the MFER (Multi-Format Electroencephalogram Recording) file parsing functionality, where improper handling of the Tag 0 field leads to a buffer overflow condition. The issue occurs at line 8719 in biosig.c, where the code expects the length of the Tag 0 field to be exactly one byte. However, if a specially crafted MFER file contains a Tag 0 with an incorrect length, the function proceeds to read beyond the allocated buffer size without adequate bounds checking. This unchecked read operation allows an attacker to overwrite the stack, potentially leading to arbitrary code execution. The vulnerability requires no authentication or user interaction and can be exploited remotely by supplying a malicious MFER file to an application or system component that uses libbiosig for EEG data processing. The CVSS v3.1 base score of 9.8 reflects the high severity, with network attack vector, low attack complexity, no privileges required, and no user interaction needed. The impact encompasses full compromise of confidentiality, integrity, and availability of affected systems. Although no known exploits are currently reported in the wild, the critical nature and ease of exploitation make this a significant threat to any organization utilizing libbiosig for EEG data analysis or related biomedical signal processing.

For European organizations, the impact of CVE-2025-54480 is substantial, particularly for healthcare providers, research institutions, and medical device manufacturers that rely on libbiosig for processing EEG and other biosignal data. Exploitation could lead to unauthorized execution of arbitrary code, resulting in data breaches involving sensitive patient information, manipulation or corruption of medical data, and potential disruption of critical healthcare services. This could undermine patient safety, violate data protection regulations such as GDPR, and cause reputational damage. Additionally, research entities using libbiosig in neuroscience or biomedical studies may face data integrity issues, compromising scientific outcomes. The vulnerability's network accessibility and lack of required privileges increase the risk of widespread exploitation if malicious actors target vulnerable systems. Given the criticality of healthcare infrastructure in Europe and the increasing integration of digital biomedical tools, this vulnerability poses a direct threat to operational continuity and data security in the sector.

To mitigate CVE-2025-54480, European organizations should immediately audit their software stacks to identify any usage of libbiosig versions 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 restrict processing of MFER files from untrusted or external sources to prevent malicious input. 2) Implement input validation and sandboxing around any component that parses MFER files to contain potential exploitation attempts. 3) Monitor network and application logs for anomalous activity related to MFER file handling, including unexpected errors or crashes. 4) Engage with The Biosig Project community or maintainers to obtain or contribute patches addressing the buffer overflow. 5) Where feasible, replace or isolate libbiosig-dependent components until a secure version is released. 6) Educate relevant staff about the risks of processing untrusted biosignal files and enforce strict access controls. These targeted measures go beyond generic advice by focusing on the specific vector (MFER file parsing) and the operational context of libbiosig usage.