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LibbiosigApplication · Libbiosig Project

CVE-2025-66045

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 65

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

A stack-based buffer overflow exists in libbiosig 3.9.1's MFER file parsing code. When processing MFER files with Tag value 65, insufficient bounds checking allows a specially crafted file to overflow a stack-allocated buffer, enabling arbitrary code execution.

MitigationUpdate to the patched version of libbiosig. Until available, disable or avoid processing untrusted MFER files with the library.

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. Identify installed libbiosig version
    Run 'pkg-config --modversion libbiosig' or check the library file version directly (e.g., 'strings libbiosig.so | grep -i version' or check the package manager installed version)
    Affected if The installed version is lower than 3.9.2 (e.g., 3.9.1 or earlier)
  2. Confirm MFER file parsing support is compiled
    Check if the libbiosig library was built with MFER support enabled. Look for 'MFER' in the library symbols ('nm -C libbiosig.so | grep -i mfer') or check the build configuration for MFER-related compile flags
    Affected if MFER parsing support is present in the compiled library (vulnerable code path exists)
  3. Identify applications or processes using libbiosig for MFER files
    Search codebase or running processes for calls to libbiosig functions that handle MFER format files. Look for function patterns like 'sopen' or 'read_mfer' when loading files with .mfer extension or MFER format detection
    Affected if Any application or tool uses libbiosig to parse MFER files from any source
  4. Assess whether untrusted MFER files are processed
    Review log files, file processing pipelines, or user upload handling to determine if MFER files from untrusted or external sources are being parsed by libbiosig-enabled software
    Affected if The environment processes MFER files from sources outside the trusted internal baseline

You are affected if libbiosig version is below 3.9.2 AND your environment uses the library to parse MFER files, especially from untrusted sources.

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 to the patched version of libbiosig. Until available, disable or avoid processing untrusted MFER files with the library.

Recommended fix Moderate confidence

libbiosig 3.9.2

  1. 1. Obtain libbiosig version 3.9.2 or later from the official Biosig Project source (https://biosig.sourceforge.net/)
  2. 2. Verify the integrity of the downloaded package using published checksums if available
  3. 3. Back up any existing libbiosig installations and dependent applications
  4. 4. Install libbiosig 3.9.2 following the project's build instructions (typically ./configure, make, make install)
  5. 5. Rebuild and redeploy any applications that link against libbiosig to ensure they use the updated library
  6. 6. Test that MFER file parsing functionality works correctly with the updated library
  7. 7. Verify that the previously vulnerable MFER parsing code (specifically Tag 65 handling) no longer exhibits the buffer overflow
Caveat Review release notes for 3.9.2 to check for any API changes that may affect existing code using libbiosig

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

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

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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-2025-66045 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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