CVE-2025-54484 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 8779 of biosig.c on the current master branch (35a819fa), when the Tag is 6:
else if (tag==6) // 0x06 "number of sequences" {
// NRec if (len>4) fprintf(stderr,"Warning MFER tag6 incorrect length %i>4\n",len); curPos += ifread(buf,1,len,hdr);
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Analysis
by VulDB Data Team • 09/02/2025
The vulnerability CVE-2025-54484 represents a critical stack-based buffer overflow in the libbiosig library version 3.9.0 and master branch commit 35a819fa, specifically within the MFER file parsing functionality. This issue stems from inadequate input validation when processing the Tag 6 field in MFER format files, which is designated for "number of sequences" and typically expects a 4-byte integer value. The flaw occurs at line 8779 in the biosig.c source file where the code fails to properly enforce bounds checking on the length parameter before processing the buffer read operation. When an attacker crafts a malicious MFER file with an oversized length field for tag 6, the code executes a read operation that exceeds the allocated buffer space, creating a predictable stack corruption scenario.
The technical implementation of this vulnerability involves the improper handling of the ifread function call which reads data into a buffer without sufficient validation of the length parameter. The code displays a warning message for incorrect length values but continues execution without preventing the overflow, allowing malicious data to overwrite adjacent stack memory. This particular implementation pattern aligns with CWE-121 Stack-based Buffer Overflow, where insufficient bounds checking permits data to overwrite stack variables and potentially executable code. The vulnerability manifests through the use of the fprintf function to display warnings, which indicates the system's attempt to handle error conditions but fails to prevent the underlying memory corruption. The specific tag 6 processing pathway creates an attack surface where an attacker can manipulate the len parameter to exceed the expected 4-byte limit, directly enabling arbitrary code execution.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with complete control over the affected system when the library is used to process untrusted MFER files. The vulnerability affects systems that utilize libbiosig for medical signal data processing, particularly in healthcare environments where such files may be automatically processed without user interaction. Attackers can leverage this vulnerability through social engineering tactics to deliver malicious MFER files via email attachments, file sharing platforms, or automated data ingestion processes. The attack chain follows standard exploitation patterns where the buffer overflow corrupts the return address on the stack, allowing an attacker to redirect program execution to malicious code. This vulnerability is particularly concerning in environments where the library is used in server applications or automated processing pipelines, as it could enable remote code execution without user interaction, aligning with ATT&CK technique T1203 Exploitation for Client Execution.
Mitigation strategies for CVE-2025-54484 should prioritize immediate patching of the libbiosig library to version 3.9.1 or later where the buffer overflow has been corrected. The fix must implement proper bounds checking for all length parameters in MFER parsing functions, particularly for tag 6 processing, ensuring that the len parameter does not exceed the maximum expected buffer size. System administrators should implement input validation measures at the application level, rejecting MFER files that contain suspicious length values or malformed structures before passing them to the libbiosig library. Network segmentation and file access controls should be enforced to limit exposure, particularly in healthcare environments where medical data processing applications may be vulnerable. Additionally, organizations should consider implementing sandboxing mechanisms for processing medical signal files, as recommended in NIST SP 800-144 guidelines for secure handling of medical data. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other medical data processing libraries, following the principles outlined in ISO/IEC 27001 security management frameworks.