Cyber Posture

CVE-2025-66043

CriticalPublic PoC

Published: 11 December 2025

Published
11 December 2025
Modified
17 December 2025
KEV Added
Patch
CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0019 40.7th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Description

Several stack-based buffer overflow vulnerabilities exists in the MFER parsing functionality of The Biosig Project libbiosig 3.9.1. A specially crafted MFER file can lead to arbitrary code execution. An attacker can provide a malicious file to trigger these vulnerabilities.When Tag…

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is 3

Mitigating Controls (NIST 800-53 r5)AI

prevent

SI-2 requires timely identification, reporting, and patching of flaws like the stack-based buffer overflow in libbiosig's MFER parsing, directly eliminating the vulnerability.

prevent

SI-10 mandates validation of information inputs such as MFER files at the parsing stage to reject specially crafted files that trigger the buffer overflow when Tag is 3.

prevent

SI-16 enforces memory protections like stack canaries and ASLR to mitigate arbitrary code execution from the stack-based buffer overflow even if unpatched.

Security SummaryAI

CVE-2025-66043 involves several stack-based buffer overflow vulnerabilities (CWE-121 and CWE-787) in the MFER parsing functionality of The Biosig Project's libbiosig version 3.9.1. These flaws, which manifest when Tag is 3, can be triggered by a specially crafted MFER file, potentially leading to arbitrary code execution.

The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), marking it as critical due to its network accessibility, low complexity, lack of required privileges or user interaction, and high impacts across confidentiality, integrity, and availability. Any unauthenticated attacker capable of supplying a malicious MFER file to an application that uses the affected library for parsing can exploit it to achieve arbitrary code execution.

Mitigation guidance is available in the Talos Intelligence advisory at https://talosintelligence.com/vulnerability_reports/TALOS-2025-2296.

Details

CWE(s)

Affected Products

libbiosig project
libbiosig
≤ 3.9.2

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Why these techniques?

The vulnerability enables arbitrary code execution via a specially crafted MFER file with network accessibility (AV:N), no privileges (PR:N), and no user interaction (UI:N), directly facilitating exploitation of public-facing applications that parse such files.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

References