LibbiosigApplication · Libbiosig Project

CVE-2025-66044

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 64

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 · moderate confidence

A stack-based buffer overflow vulnerability exists in the MFER file parsing functionality of libbiosig 3.9.1. When parsing MFER files with Tag value 64, the parser fails to properly validate input bounds before copying data to a fixed-size stack buffer, allowing an attacker to overwrite stack frames and achieve arbitrary code execution.

MitigationUpdate libbiosig to the latest patched version. If patching is not immediately possible, restrict processing of untrusted MFER files and disable MFER format support in affected deployments until the update can be 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. Locate libbiosig installation
    Search for the libbiosig library file on the system. On Linux/Unix check common library paths such as /usr/lib, /usr/local/lib, or custom installation directories. Look for files named libbiosig.so, libbiosig.a, or libbiosig.dylib. On Windows check System32 or application-specific directories for biosig.dll or libbiosig.dll.
    Affected if The libbiosig library file exists on the system
  2. Determine installed version
    Extract version information from the library file. On Linux this may be embedded in the filename, obtainable via 'strings' command on the library, or via 'ldconfig -l' if the library is registered. Compare your version against the affected range of versions earlier than 3.9.2.
    Affected if Installed version is earlier than 3.9.2
  3. Check if MFER format support is active
    Identify applications or services that use libbiosig and determine whether MFER file format parsing is enabled or used. This may require reviewing application configuration files, checking which format parsers are loaded, or examining logs for MFER file processing activity.
    Affected if Applications process MFER files using the vulnerable libbiosig installation

A system is affected if it runs libbiosig version earlier than 3.9.2 AND processes MFER files, since the stack buffer overflow only triggers during MFER parsing with Tag value 64.

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

Update libbiosig to the latest patched version. If patching is not immediately possible, restrict processing of untrusted MFER files and disable MFER format support in affected deployments until the update can be applied.

Recommended fix High confidence

libbiosig 3.9.2

  1. 1. Identify the current version of libbiosig installed on the system (e.g., check via package manager, or run biosig version command if available)
  2. 2. Obtain libbiosig version 3.9.2 from the official Biosig Project repository or release channels
  3. 3. Uninstall or remove the existing vulnerable libbiosig installation
  4. 4. Install libbiosig version 3.9.2 using standard build/installation procedures (e.g., ./configure, make, make install for source builds)
  5. 5. Verify that version 3.9.2 is now installed and that MFER file parsing functions correctly
  6. 6. Re-test any applications that rely on libbiosig to ensure normal operation

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

Fix this in Libbiosig Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get the upgrade done

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Scan for this in your stack

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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-2025-66044 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

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