CVE-2025-54488 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 arises in the MFER (Multi-File EEG Record) parsing functionality, where improper handling of the length of Tag 13 data leads to a buffer overflow on the stack. The vulnerable code segment, located around line 8850 in biosig.c, fails to adequately validate the length of the input data before reading it into a fixed-size buffer. When a specially crafted MFER file with a Tag 13 length greater than 8 bytes is processed, this results in overwriting adjacent memory on the stack, potentially allowing an attacker to execute arbitrary code. The vulnerability does not require any privileges or user interaction, and can be exploited remotely by supplying a malicious MFER file to an application using libbiosig for EEG data processing. The CVSS v3.1 base score of 9.8 reflects the high impact on confidentiality, integrity, and availability, combined with the ease of exploitation over a network without authentication. Although no public exploits have been reported yet, the critical nature of this vulnerability demands immediate attention from users of libbiosig, especially in medical and research environments where EEG data processing is common.

For European organizations, particularly those in healthcare, neuroscience research, and medical device manufacturing, this vulnerability poses a significant risk. libbiosig is widely used for biosignal processing, including EEG data analysis, which is critical in clinical diagnostics and research. Exploitation could lead to arbitrary code execution on systems processing malicious MFER files, potentially compromising patient data confidentiality, disrupting diagnostic services, and undermining the integrity of research data. Given the criticality of healthcare infrastructure in Europe and stringent data protection regulations such as GDPR, a successful attack could result in severe operational disruptions, legal penalties, and reputational damage. Additionally, research institutions and companies developing medical devices that incorporate libbiosig could face intellectual property theft or sabotage. The vulnerability's network exploitable nature means that any system accepting MFER files from external or untrusted sources is at risk, increasing the attack surface across European healthcare and research networks.

1. Immediate patching: Although no official patches are linked yet, organizations should monitor The Biosig Project repositories and security advisories for updates addressing this vulnerability and apply them promptly. 2. Input validation: Implement strict validation and sanitization of MFER files before processing, including enforcing maximum length constraints on Tag 13 data to prevent buffer overflows. 3. Application hardening: Use compiler-level protections such as stack canaries, ASLR (Address Space Layout Randomization), and DEP (Data Execution Prevention) to mitigate exploitation impact. 4. Network controls: Restrict and monitor sources of MFER files, especially from external or untrusted networks, to reduce exposure. 5. Runtime monitoring: Deploy intrusion detection systems and endpoint protection solutions capable of detecting anomalous behavior indicative of exploitation attempts. 6. Code review and fuzz testing: For organizations maintaining forks or custom versions of libbiosig, conduct thorough code audits and fuzz testing focused on MFER parsing to identify and remediate similar vulnerabilities proactively. 7. Incident response readiness: Prepare for potential exploitation scenarios by establishing response plans specific to this vulnerability, including forensic analysis and containment procedures.