CVE-2025-64736: Libbiosig Information Disclosure Flaw

CVE-2025-64736 Overview

An out-of-bounds read vulnerability exists in the ABF parsing functionality of The Biosig Project libbiosig. This vulnerability affects version 3.9.2 and the Master Branch (5462afb0). The flaw occurs when processing specially crafted .abf files, which can lead to an information leak. An attacker can provide a malicious file to trigger this vulnerability, potentially exposing sensitive memory contents or causing application instability.

Critical Impact

This vulnerability enables attackers to read data beyond allocated memory boundaries when processing malicious ABF files, leading to potential information disclosure and denial of service conditions.

Affected Products

• libbiosig 3.9.2
• libbiosig Master Branch (5462afb0)
• Applications and systems that utilize libbiosig for ABF file parsing

Discovery Timeline

• 2026-03-03 - CVE-2025-64736 published to NVD
• 2026-03-05 - Last updated in NVD database

Technical Details for CVE-2025-64736

Vulnerability Analysis

This vulnerability is classified as CWE-125 (Out-of-Bounds Read), a memory corruption vulnerability that occurs when the software reads data past the end of an intended buffer. In the context of libbiosig's ABF parsing functionality, the vulnerability manifests when processing specially crafted .abf files.

The ABF (Axon Binary File) format is commonly used in electrophysiology to store biological signal data. When libbiosig parses these files, insufficient boundary checks allow an attacker to craft a malicious file that causes the parser to read memory locations outside the allocated buffer. This can result in the disclosure of sensitive information that resides in adjacent memory regions, as well as potential application crashes leading to denial of service.

The local attack vector requires user interaction, meaning an attacker must convince a victim to open the malicious .abf file using an application that relies on the vulnerable libbiosig library.

Root Cause

The root cause of this vulnerability lies in improper input validation within the ABF file parsing routines of libbiosig. Specifically, the parser fails to adequately verify that data lengths and offsets specified within the ABF file structure fall within the bounds of the allocated memory buffer. When processing a crafted file containing malicious length or offset values, the parser attempts to read data from memory locations beyond the buffer boundary.

Attack Vector

The attack requires local access and user interaction. An attacker would need to:

1. Craft a malicious .abf file with manipulated header values or data offsets designed to trigger out-of-bounds memory reads
2. Deliver the malicious file to the victim through email, file sharing, or other means
3. Convince the victim to open the file using an application that incorporates the vulnerable libbiosig library

Upon parsing the malicious file, the vulnerable code path will read beyond allocated memory boundaries. This can leak sensitive data from adjacent memory regions or cause the application to crash if it attempts to access protected memory.

Technical details regarding the specific exploitation mechanism can be found in the Talos Intelligence Vulnerability Report.

Detection Methods for CVE-2025-64736

Indicators of Compromise

• Unexpected crashes or abnormal termination of applications using libbiosig when processing ABF files
• Memory access violations or segmentation faults logged during ABF file parsing operations
• Suspicious .abf files with anomalous header values or unusually structured data sections
• Applications exhibiting unusual memory consumption patterns when processing ABF files

Detection Strategies

• Monitor for application crashes associated with libbiosig or ABF file processing components
• Implement file integrity monitoring to detect delivery of potentially malicious .abf files to user directories
• Deploy endpoint detection solutions capable of identifying memory access violations and out-of-bounds read attempts
• Review system logs for segmentation faults or access violation errors in processes that utilize libbiosig

Monitoring Recommendations

• Enable detailed logging for applications that process ABF files to capture parsing errors and anomalies
• Configure endpoint protection to alert on unusual file access patterns involving .abf files
• Monitor network file transfers and email attachments for .abf files from untrusted sources
• Implement application sandboxing to contain potential exploitation attempts when processing untrusted ABF files

How to Mitigate CVE-2025-64736

Immediate Actions Required

• Identify all systems and applications in your environment that utilize the vulnerable libbiosig library
• Restrict processing of .abf files from untrusted or unknown sources until patches are applied
• Update libbiosig to a patched version when available from The Biosig Project
• Implement network segmentation to limit the exposure of systems running vulnerable software

Patch Information

Organizations should monitor The Biosig Project for official security patches addressing this vulnerability. Review the Talos Intelligence Vulnerability Report for the latest information regarding available fixes and remediation guidance.

When patches become available, prioritize updating:

• libbiosig 3.9.2 installations
• Any installations using the Master Branch at commit 5462afb0 or earlier

Workarounds

• Disable or restrict ABF file processing functionality in applications where it is not strictly required
• Implement strict input validation at the application layer before passing ABF files to libbiosig
• Process .abf files only within isolated or sandboxed environments to contain potential exploitation
• Block receipt of .abf file attachments at the email gateway from untrusted external sources

# Configuration example - Restrict ABF file processing to sandboxed environment
# Example AppArmor profile restriction for libbiosig-dependent applications
# Add to /etc/apparmor.d/local/your-biosig-app

# Deny direct memory access
deny /dev/mem rwx,
deny /dev/kmem rwx,

# Restrict file access to specific directories
/path/to/trusted/abf/files/** r,
deny /tmp/*.abf rw,