CVE-2025-53511: 
Linux Debian vulnerability analysis and mitigation

A heap-based buffer overflow vulnerability exists in the MFER parsing functionality of The Biosig Project libbiosig 3.9.0 and Master Branch (35a819fa). The vulnerability was discovered by Mark Bereza and Lilith of Cisco Talos and was disclosed on August 25, 2025. This security flaw has been assigned CVE-2025-53511 and received a CVSS v3.1 base score of 9.8 (Critical) (Talos, NVD).

The vulnerability exists in the MFER (Medical waveform Format Encoding Rules) parsing functionality of libbiosig. The issue stems from a mismatch between the initial size allocated for the hdr->CHANNEL array and the default value of hdr->NS in the MFER processing code. When processing MFER files, hdr->NS is initialized to 1, but the hdr->CHANNEL array is allocated with a size of 0, leading to a heap-based buffer overflow condition. The vulnerability has been classified as CWE-122 (Heap-based Buffer Overflow) and can be triggered by providing a specially crafted MFER file (Talos).

The vulnerability allows an attacker to achieve arbitrary code execution by providing a malicious file. The critical CVSS score of 9.8 indicates severe potential impact, with high ratings for confidentiality, integrity, and availability. The vulnerability requires no privileges or user interaction and can be exploited remotely (NVD, Talos).

The vulnerability was patched on August 24, 2025. Users should upgrade to a version newer than libbiosig 3.9.0 or apply the latest security patches to the Master Branch (after commit 35a819fa) (Talos).