Overview

The Biosig Project libbiosig, a widely used software library for biomedical signal processing, is currently at risk due to a critical buffer overflow vulnerability identified as CVE-2025-54491. This vulnerability could allow an attacker to execute arbitrary code on a system running a vulnerable version of the software, leading to potential system compromise or data leakage. The severity of this vulnerability and its broad potential impact underline the urgent need for timely mitigation steps to protect systems and data.

Vulnerability Summary

CVE ID: CVE-2025-54491
Severity: Critical (CVSS: 9.8)
Attack Vector: Local file system
Privileges Required: Low
User Interaction: Required
Impact: Potential system compromise and data leakage

Affected Products

Product | Affected Versions

The Biosig Project libbiosig | 3.9.0, Master Branch (35a819fa)

How the Exploit Works

The vulnerability resides in the MFER parsing functionality of libbiosig. An attacker can exploit this vulnerability by crafting a malicious MFER file that triggers a stack-based buffer overflow. This buffer overflow occurs on line 9191 of biosig.c when the Tag is 65, leading to arbitrary code execution. The attacker would need to trick the user into opening the malicious file, which could be done through various social engineering tactics.

Conceptual Example Code

While it is not advisable to provide real exploit code, a conceptual example might look like this:

#include <stdio.h>
#include <stdlib.h>
int main() {
// MFER file with malicious payload
char buf[1000] = "malicious_payload";
// Open the vulnerable file
FILE *hdr = fopen("vulnerable.mfer", "wb");
// Write the payload to the file
fwrite(buf, sizeof(char), sizeof(buf), hdr);
fclose(hdr);
return 0;
}

In this example, a buffer `buf` is filled with a malicious payload and written to a MFER file `vulnerable.mfer`. When this file is opened with the vulnerable version of libbiosig, the payload is executed, potentially compromising the system or leading to data leakage.

Mitigation Guidance

Users are strongly advised to apply the vendor-supplied patch as soon as possible. If a patch cannot be applied immediately, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as a temporary mitigation measure. These tools can help detect and block attempts to exploit this vulnerability. Additionally, users should be cautious of unsolicited files and consider scanning all files with an up-to-date antivirus solution before opening.