Overview
The Biosig Project libbiosig 3.9.0 and Master Branch (35a819fa) is a library widely used for handling biomedical signal data. It has been discovered that a severe stack-based buffer overflow vulnerability (CVE-2025-54490) exists in the MFER parsing functionality of this library. This vulnerability, if exploited, could lead to arbitrary code execution, posing a grave threat to the security and integrity of systems running the vulnerable versions of the library. With a CVSS Severity Score of 9.8, it is essential for cybersecurity professionals, system administrators, and developers to understand the nature of this vulnerability and how to mitigate its potential impact.
Vulnerability Summary
CVE ID: CVE-2025-54490
Severity: Critical (CVSS: 9.8)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
The Biosig Project libbiosig | 3.9.0 and Master Branch (35a819fa)
How the Exploit Works
The vulnerability resides in the MFER parsing functionality of the Biosig Project libbiosig 3.9.0 and Master Branch (35a819fa). It triggers on line 9090 of biosig.c, when the Tag is 64. In this scenario, an overflowed buffer `tmp` is declared instead of `buf`. Although `tmp` is larger than `buf`, measuring 256 bytes, a stack overflow can occur if `len` is encoded using multiple octets and is greater than 256. This stack-based buffer overflow vulnerability can be exploited by an attacker providing a specially crafted MFER file, leading to arbitrary code execution.
Conceptual Example Code
While we can’t provide a real MFER file, the exploit would conceptually involve creating a malicious MFER file with a `len` value greater than 256. Below is a simplistic representation:
# Pseudocode for creating a malicious MFER file
def create_malicious_file():
len_value = generate_len_value() # This would generate a len value > 256
tag_value = 64 # The tag value that triggers the vulnerability
mfer_file = MFERFile()
mfer_file.set_tag(tag_value)
mfer_file.set_len(len_value)
mfer_file.save("malicious.mfer")This pseudocode illustrates the concept of how an attacker might create a malicious MFER file to exploit the vulnerability. The actual exploit would involve more complex manipulations and a deep understanding of the MFER file format and the Biosig library.
Mitigation
Users of the affected versions of The Biosig Project libbiosig are strongly recommended to apply patches provided by the vendor as soon as they are available. In the meantime, using a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) can serve as a temporary mitigation, helping to detect and prevent attempts to exploit the vulnerability. However, these measures are not foolproof and cannot replace the need for a patched and updated system.
