CVE-2025-66046
Summary
CVE-2025-66046 describes a critical stack-based buffer overflow vulnerability within the MFER parsing functionality of The Biosig Project's libbiosig version 3.9.1. Exploitation of this vulnerability allows an attacker to achieve arbitrary code execution by providing a specially crafted MFER file.
Technical Details
CVE-2025-66046 arises from insufficient bounds checking during the parsing of MFER (Medical Format for Exchanging Recordings) files within libbiosig 3.9.1. Specifically, when processing MFER files, the application fails to properly validate the size of data being written to a stack-allocated buffer. This occurs during the handling of Tag 67 within the MFER parsing logic. An attacker can craft a malicious MFER file containing an oversized data payload associated with Tag 67, causing the buffer to overflow. This overflow overwrites adjacent memory regions on the stack, potentially including return addresses. By carefully controlling the overflowed data, an attacker can redirect program execution to arbitrary code, leading to complete system compromise. The vulnerability is triggered when the application attempts to parse the malicious MFER file. The lack of proper input validation is the root cause of the vulnerability.
The attack vector involves supplying a malicious MFER file to an application that utilizes the vulnerable libbiosig library. This can be achieved through various means, such as uploading the file to a web server, opening it in a desktop application, or processing it in a command-line tool. The specific method of delivery depends on how libbiosig is integrated into the target system.
Affected Products and Versions
- libbiosig_project libbiosig 3.9.1
Impact Assessment
Successful exploitation of CVE-2025-66046 can lead to a complete compromise of the affected system. An attacker can execute arbitrary code with the privileges of the application processing the malicious MFER file. This can result in:
- Arbitrary Code Execution: The attacker gains the ability to execute arbitrary code on the system.
- Data Breach: Sensitive data stored on the system can be accessed and exfiltrated by the attacker.
- System Compromise: The attacker can gain full control of the system, including installing malware, modifying system configurations, and launching further attacks.
- Denial of Service: The vulnerability can be exploited to crash the application or the entire system, leading to a denial of service.
Remediation
Immediate Actions
- Upgrade libbiosig: Upgrade to a patched version of libbiosig that addresses the vulnerability. Contact the libbiosig project for the latest security updates.
- Input Validation: If possible, implement strict input validation on MFER files before processing them with libbiosig. This can help to prevent malicious files from being processed.
Long-term Solutions
- Code Review: Conduct a thorough code review of libbiosig to identify and fix other potential vulnerabilities.
- Fuzzing: Implement fuzzing techniques to automatically test libbiosig for vulnerabilities.
References
Detection & Scanning
Detecting CVE-2025-66046 requires identifying systems running the vulnerable version of libbiosig (3.9.1) and monitoring for suspicious activity related to MFER file processing. Network intrusion detection systems (IDS) and endpoint detection and response (EDR) solutions can be configured to detect attempts to exploit this vulnerability. Vulnerability scanners can also be used to identify systems running the vulnerable version of libbiosig.
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