CVE-2025-54484 is a stack-based buffer overflow vulnerability identified in The Biosig Project's libbiosig library, specifically in the MFER file parsing code. The vulnerability is triggered when the parser encounters tag 6 (0x06), which represents the "number of sequences" in the MFER format. The code fails to properly validate the length of the data associated with this tag, allowing an attacker to supply a maliciously crafted MFER file that exceeds the expected length (greater than 4 bytes). This improper length check leads to a buffer overflow on the stack, which can overwrite the return address or other control data, enabling arbitrary code execution. The vulnerability exists in libbiosig version 3.9.0 and the current master branch (commit 35a819fa). Exploitation requires no privileges or user interaction and can be performed remotely by delivering a malicious MFER file to an application using libbiosig for parsing. The CVSS v3.1 score of 9.8 reflects the critical nature of this flaw, with network attack vector, low attack complexity, no privileges required, and full impact on confidentiality, integrity, and availability. Although no public exploits have been reported yet, the vulnerability's characteristics make it a high-risk issue for any software relying on libbiosig for biomedical signal processing or related tasks.

For European organizations, the impact of CVE-2025-54484 can be severe, especially in sectors relying on biomedical signal processing, such as healthcare providers, medical device manufacturers, and research institutions. Successful exploitation could lead to arbitrary code execution, allowing attackers to compromise systems, steal sensitive patient data, disrupt medical services, or pivot within networks. This could result in significant data breaches, operational downtime, regulatory penalties under GDPR, and damage to organizational reputation. Given the criticality and ease of exploitation, even a single malicious MFER file could compromise critical infrastructure or research environments. The vulnerability also poses risks to software supply chains that incorporate libbiosig, potentially affecting a broader range of applications beyond direct biomedical use. The lack of known exploits in the wild currently provides a window for proactive mitigation, but the threat remains imminent.

1. Monitor The Biosig Project repositories and security advisories for an official patch addressing CVE-2025-54484 and apply it immediately upon release. 2. Until a patch is available, implement strict input validation to reject MFER files with tag 6 data lengths exceeding the expected maximum (4 bytes). 3. Employ sandboxing or containerization for applications processing MFER files to limit the impact of potential exploitation. 4. Restrict network and user access to systems that parse MFER files, especially from untrusted sources. 5. Conduct code audits and static analysis on any custom or third-party software using libbiosig to identify and mitigate unsafe parsing practices. 6. Deploy runtime protections such as stack canaries, ASLR, and DEP to reduce exploitation success. 7. Educate developers and system administrators about the risks of processing untrusted biomedical data formats and enforce secure coding practices. 8. Implement network-level monitoring for anomalous activity related to MFER file handling or unexpected process behavior in affected systems.