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LibbiosigApplication · Libbiosig Project

CVE-2025-66043

CRITICAL · 9.8 CVSS v3.1 Published 2025-12-11
Fix available
A fix is available. Upgrade to 3.9.2 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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 is 3

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Stack-based buffer overflow in libbiosig 3.9.1 MFER file parser, triggered when processing Tag 3 in a specially crafted MFER file, allowing arbitrary code execution.

MitigationValidate and sanitize MFER file input before parsing; update to patched version if available; restrict processing of untrusted MFER files until fix is applied.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
LibbiosigApplication
Affected:< 3.9.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if libbiosig is installed and identify its version
    Run 'pkg-config --modversion libbiosig' or check for the library file (e.g., libbiosig.so, libbiosig.a) and review any version metadata. If building from source, check the version string in source files or the installed headers.
    Affected if The installed version is less than 3.9.2 or the version cannot be determined and the library is present
  2. Verify MFER file format support is enabled in libbiosig
    Inspect the libbiosig configuration or build settings. Check for the presence of MFER-related code files (e.g., mfer.c, mfer.h) in the installed library or source directory. Review compile-time flags such as MFER_ENABLED or similar.
    Affected if MFER support is compiled into the library (the MFER parser code is present)
  3. Identify applications or tools that use libbiosig to process MFER files
    Search for executables or scripts that link against libbiosig and are used for processing medical data files. Look for commands that invoke the library to parse MFER format files. Check process logs or file access patterns for recent MFER file processing activity.
    Affected if Any application uses libbiosig to parse MFER files in the environment
  4. Locate MFER files that may have been processed
    Search the filesystem for files with .mfer extension or files identified as MFER format. Review any recent file access logs or application usage records involving MFER files.
    Affected if MFER files exist in the environment or have been recently processed by libbiosig-based tools

You are affected if libbiosig version is below 3.9.2 AND MFER file format support is enabled AND MFER files are processed in your environment.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 3.9.2 or later
Fixed in 3.9.2
Interim mitigation

Validate and sanitize MFER file input before parsing; update to patched version if available; restrict processing of untrusted MFER files until fix is applied.

Recommended fix High confidence

libbiosig 3.9.2

  1. 1. Identify the current version of libbiosig installed in your environment by checking your dependencies or using pkg-config --modversion libbiosig
  2. 2. Confirm the installed version is 3.9.1 or earlier (versions < 3.9.2 are affected by this vulnerability)
  3. 3. Obtain libbiosig version 3.9.2 or later from the official source (https://biosig.sourceforge.net/ or your distribution's package repository)
  4. 4. Upgrade libbiosig to version 3.9.2 or newer
  5. 5. Rebuild or recompile any applications that link against libbiosig to ensure they use the updated library
  6. 6. Verify the new version is correctly installed and in use
  7. 7. Re-test MFER file parsing functionality to confirm the fix does not break legitimate operations

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Libbiosig Scoped from the published advisory
  • Consultation3.0 h
  • Implementation10.0 h
  • Testing6.0 h
  • Review / QA3.0 h
22.0 hours of engineering $3,840
Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-66043 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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