CVE-2025-54493 in libbiosig
Summary
by MITRE • 08/25/2025
A stack-based buffer overflow vulnerability exists in the MFER parsing functionality of The Biosig Project libbiosig 3.9.0 and Master Branch (35a819fa). A specially crafted MFER file can lead to arbitrary code execution. An attacker can provide a malicious file to trigger this vulnerability.This vulnerability manifests on line 9184 of biosig.c on the current master branch (35a819fa), when the Tag is 131:
else if (tag==131) //0x83 {
// Patient Age if (len!=7) fprintf(stderr,"Warning MFER tag131 incorrect length %i!=7\n",len); curPos += ifread(buf,1,len,hdr);
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Analysis
by VulDB Data Team • 09/03/2025
The vulnerability CVE-2025-54493 represents a critical stack-based buffer overflow within the MFER parsing component of libbiosig version 3.9.0 and the master branch at commit 35a819fa. This flaw resides in the biosig.c source file at line 9184 within the handling logic for MFER tag 131, which corresponds to patient age data parsing. The vulnerability stems from insufficient input validation and bounds checking when processing the length parameter associated with this specific tag, creating a potential pathway for remote code execution through crafted malicious MFER files. The issue manifests when the system attempts to read data into a buffer without proper verification of the expected data length, allowing attackers to overflow the allocated stack space and potentially overwrite adjacent memory regions including return addresses and control data.
The technical implementation of this vulnerability follows established patterns described in CWE-121 Stack-based Buffer Overflow, where the application fails to properly validate the length parameter before performing memory operations. The code structure at line 9184 demonstrates a clear failure to enforce bounds checking on the variable length parameter, which is read directly from the MFER file without adequate validation. While the code does include a warning message for incorrect length values, this does not prevent the actual buffer overflow from occurring. The vulnerability is particularly dangerous because it operates within the context of file parsing functionality that is commonly used in medical data processing systems, making it attractive to threat actors seeking to compromise healthcare information systems. The attack vector requires only that an attacker can convince a victim to process a specially crafted MFER file, which could occur through social engineering, automated scanning, or supply chain compromise.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with potential persistence mechanisms and privilege escalation capabilities within systems processing medical data. According to ATT&CK framework tactic TA0002 Execution and TA0004 Privilege Escalation, this vulnerability could enable adversaries to establish persistent access to systems handling sensitive medical information. The exploitation of this buffer overflow could result in complete system compromise, data exfiltration, or disruption of medical services, particularly in healthcare environments where such systems are critical for patient care. The vulnerability affects systems using libbiosig for processing physiological data, which includes various medical monitoring and diagnostic applications that process structured data files. Organizations implementing this library in production environments face significant risk, as the vulnerability could be exploited to gain unauthorized access to patient medical records, potentially violating HIPAA compliance requirements and exposing sensitive health information.
Mitigation strategies for CVE-2025-54493 should prioritize immediate patching of affected systems, as the vulnerability exists in both the released version 3.9.0 and the master branch. Security teams should implement input validation measures at the application level to prevent malformed MFER files from being processed, including length validation and memory boundary checks. Network segmentation and file scanning capabilities should be enhanced to detect and block suspicious MFER files before they reach vulnerable systems. Additionally, organizations should consider implementing runtime protections such as stack canaries and address space layout randomization to reduce exploit reliability. The vulnerability demonstrates the importance of proper memory management practices and input validation in security-critical applications, particularly those handling sensitive data in regulated environments. System administrators should monitor for exploitation attempts and maintain updated threat intelligence on potential attack patterns targeting medical data processing systems. Regular security assessments and code reviews should be conducted to identify similar patterns in other components of the biosig library or related medical data processing software, ensuring comprehensive protection against similar vulnerabilities.