CVE-2025-54485 is a stack-based buffer overflow vulnerability identified in The Biosig Project's libbiosig library, specifically affecting version 3.9.0 and the master branch (commit 35a819fa). The vulnerability is located in the MFER (Medical Format for Electroencephalographic Recordings) file parsing code, particularly when handling tag 8 data. The flaw occurs due to insufficient length validation before reading data into a fixed-size stack buffer, allowing an attacker to overflow the buffer by providing a maliciously crafted MFER file with an incorrect length field. This memory corruption can lead to arbitrary code execution, enabling an attacker to run code with the privileges of the application using libbiosig. The vulnerability is exploitable remotely without authentication or user interaction, as it only requires the processing of a crafted MFER file. The CVSS v3.1 base score is 9.8, reflecting its critical severity with network attack vector, low attack complexity, no privileges required, and no user interaction needed. The vulnerability impacts confidentiality, integrity, and availability, making it a severe threat. Currently, no public patches or known exploits are reported, but the technical details indicate a high risk of exploitation once weaponized. Libbiosig is used primarily in biomedical signal processing applications, including EEG data analysis, which are common in healthcare and research environments. The vulnerability's presence in a widely used open-source library increases the risk of supply chain attacks or indirect exploitation through dependent software.

For European organizations, the impact of CVE-2025-54485 is significant, especially in sectors relying on biomedical signal processing such as hospitals, research institutions, and medical device manufacturers. Exploitation could lead to unauthorized code execution within critical systems, potentially compromising patient data confidentiality, altering medical data integrity, or causing denial of service in diagnostic tools. This could disrupt healthcare delivery and research activities, leading to financial losses, regulatory penalties under GDPR, and reputational damage. The vulnerability's remote exploitability without authentication increases the attack surface, particularly for organizations that process MFER files from external sources or third-party vendors. Additionally, the criticality of healthcare infrastructure in Europe makes this vulnerability a potential target for cyber espionage or sabotage. The lack of known exploits currently provides a window for proactive mitigation, but the high CVSS score demands urgent attention to prevent future attacks.

1. Monitor The Biosig Project repositories and security advisories closely for official patches addressing CVE-2025-54485 and apply them immediately upon release. 2. Until patches are available, implement strict input validation and sanitization on all MFER files before processing to detect and reject malformed or suspicious files, especially those with tag 8 length fields exceeding expected values. 3. Employ sandboxing or containerization techniques to isolate the libbiosig processing environment, limiting the impact of potential exploitation. 4. Restrict access to systems processing MFER files to trusted sources and networks, reducing exposure to malicious inputs. 5. Conduct code audits and static analysis on any custom or third-party software integrating libbiosig to identify and remediate unsafe usage patterns. 6. Enhance monitoring and logging around file ingestion points to detect anomalous activity or crashes indicative of exploitation attempts. 7. Educate staff handling biomedical data about the risks of processing untrusted files and enforce strict operational security policies. 8. Consider alternative libraries or tools with no known vulnerabilities for MFER parsing if immediate patching is not feasible.