Overview
An alarming security vulnerability, CVE-2025-54481, has been identified in The Biosig Project libbiosig 3.9.0 and Master Branch (35a819fa), posing a significant threat to system integrity and data privacy. This stack-based buffer overflow vulnerability resides in the MFER parsing functionality, leading to potential system compromise or data leakage if successfully exploited. Given the widespread usage of The Biosig Project libbiosig in various applications, this vulnerability poses serious risks to numerous systems and their users worldwide.
Vulnerability Summary
CVE ID: CVE-2025-54481
Severity: Critical, CVSS 9.8
Attack Vector: Local/Network
Privileges Required: None
User Interaction: Required
Impact: System Compromise, Data Leakage
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Product | Affected Versions
The Biosig Project libbiosig | 3.9.0 and Master Branch (35a819fa)
How the Exploit Works
The vulnerability exploits the MFER parsing functionality in The Biosig Project libbiosig. An attacker can initiate an overflow by providing a specially crafted MFER file. The overflow occurs due to the buffer ‘v’, which is smaller in size (17 bytes). The critical vulnerability triggers when the Tag value is 3 in the code. The overflowed buffer is ‘v’ and not ‘buf. Even much smaller values of ‘len’, those encoded using a single octet, can trigger an overflow in this code path.
Conceptual Example Code
Given below is a conceptual example of how the vulnerability might be exploited. Here, a malicious MFER file is submitted to the system:
# Malicious MFER file creation
$ echo "malicious_payload" > exploit.mfer
# Sending malicious MFER file to the target system
$ curl -X POST -H "Content-Type: application/octet-stream" --data-binary @exploit.mfer http://target.example.com/vulnerable_endpointIn this example, a malicious payload is created and stored in an MFER file. The file is then sent to a vulnerable endpoint on the target system.
Mitigation Guidance
To mitigate this vulnerability, users are strongly advised to apply the vendor provided patch as soon as possible. If a patch cannot be applied immediately, the use of a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as temporary mitigation, alerting administrators to potential exploitation attempts.