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LibbiosigApplication · Libbiosig Project

CVE-2025-66046

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 67

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 MFER file parsing in libbiosig 3.9.1 allows arbitrary code execution via specially crafted files, specifically triggered when parsing Tag 67. The vulnerability results from insufficient bounds checking during MFER format parsing.

MitigationUpdate to patched version of libbiosig if available; otherwise implement proper length validation and bounds checking in MFER parser for Tag 67 and adjacent tags before any buffer operations.

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 libbiosig library version
    Run 'pkg-config --modversion biosig' or check for libbiosig in installed packages via package manager (dpkg, rpm, brew, etc.)
    Affected if Version is lower than 3.9.2 or version cannot be determined (indicating older install)
  2. Verify MFER file support is compiled in
    Check biosig configuration: run 'sigfmt -V' or inspect biosig-config --cflags output for MFER support, or examine compiled binary for MFER-related symbols
    Affected if MFER support is present and the library handles MFER file parsing
  3. Identify MFER file processing in your environment
    Search for files with .mfer extension or look for applications/systems that process MFER medical recording data (common in physiological recording systems)
    Affected if MFER files are present or MFER data streams are being processed
  4. Inspect Tag 67 handling in MFER parser
    If source code is available, examine the MFER parser implementation for Tag 67 handling; if binary only, note that the vulnerability exists in the tag length field processing for Tag 67
    Affected if The library parses MFER files and processes Tag 67 without bounds checking on the length field
  5. Confirm library is used by dependent applications
    Run 'ldd <your_application>' or check application dependencies to see if libbiosig is linked, or check for biosig library calls in application logs/profiles
    Affected if Applications link against libbiosig and process MFER input

You are affected if your environment uses libbiosig version below 3.9.2 with MFER file parsing enabled and processes MFER files that could contain specially crafted Tag 67 data.

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 patched version of libbiosig if available; otherwise implement proper length validation and bounds checking in MFER parser for Tag 67 and adjacent tags before any buffer operations.

Recommended fix High confidence

libbiosig 3.9.2

  1. 1. Obtain libbiosig version 3.9.2 from the official Biosig Project repository or distribution source.
  2. 2. Before upgrading, backup any existing configurations and data related to libbiosig.
  3. 3. Uninstall the current version of libbiosig (versions prior to 3.9.2).
  4. 4. Install libbiosig version 3.9.2 using the standard build and installation process for your platform (e.g., ./configure, make, make install).
  5. 5. Verify the installation by checking the installed version matches 3.9.2.
  6. 6. Recompile or relink any applications that depend on libbiosig to ensure they use the new library version.

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

Fix this in Libbiosig Scoped from the published advisory
  • Consultation3.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA3.0 h
18.0 hours of engineering $3,180
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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-2025-66046 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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