CVE-2025-53511 is a critical heap-based buffer overflow vulnerability identified in the MFER parsing functionality of The Biosig Project's libbiosig library, specifically affecting versions 3.9.0 and the Master Branch (commit 35a819fa). Libbiosig is an open-source library used for biosignal processing, including EEG, ECG, and other physiological data formats. The vulnerability arises when the library processes a specially crafted MFER (Medical Format for Electroencephalography Recordings) file, which can cause a heap overflow due to improper bounds checking during parsing. This overflow can be exploited by an attacker to execute arbitrary code on the affected system without requiring any privileges or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). The flaw impacts confidentiality, integrity, and availability, allowing potential full system compromise. Although no known exploits are currently reported in the wild, the high CVSS score of 9.8 underscores the severity and ease of exploitation. Given libbiosig’s role in medical and research environments, exploitation could lead to manipulation or disruption of sensitive biosignal data processing, potentially affecting clinical decision-making or research outcomes. The lack of available patches at the time of publication necessitates immediate attention to mitigate risk.

For European organizations, particularly those in healthcare, biomedical research, and medical device manufacturing, this vulnerability poses a significant risk. Many European hospitals and research institutions rely on biosignal processing tools that may incorporate libbiosig for EEG, ECG, or other physiological data analysis. Exploitation could lead to unauthorized code execution on critical systems, resulting in data breaches of sensitive patient information, manipulation of medical data, or disruption of medical device functionality. This could undermine patient safety, violate GDPR regulations due to data confidentiality breaches, and cause operational downtime. Additionally, research institutions could suffer data integrity issues, impacting scientific outcomes and reputations. The vulnerability’s network-exploitable nature means that any system processing untrusted MFER files—such as shared research databases or medical imaging servers—could be targeted remotely, increasing the attack surface. The absence of required authentication or user interaction further elevates the threat level for European entities relying on this software.

European organizations should immediately audit their software stacks to identify any use of libbiosig versions 3.9.0 or the affected master branch. Until an official patch is released, organizations should implement strict input validation and sandboxing measures around any component that processes MFER files to contain potential exploitation. Network-level controls such as restricting inbound traffic to systems handling biosignal data and employing intrusion detection systems tuned for anomalous file parsing behaviors can help detect exploitation attempts. Additionally, organizations should consider isolating biosignal processing environments from critical infrastructure and applying application whitelisting to prevent unauthorized code execution. Collaborating with software maintainers to prioritize patch development and testing is essential. For environments where patching is delayed, disabling or removing MFER file support temporarily can reduce risk. Finally, monitoring threat intelligence feeds for emerging exploits related to this CVE will enable timely response to active threats.