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LibbiosigApplication · Libbiosig Project

CVE-2025-54491

CRITICAL · 9.8 CVSS v3.1 Published 2025-08-25
Fix available
A fix is available. Upgrade to 3.9.1 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
A stack-based buffer overflow vulnerability exists in the MFER parsing functionality of The Biosig Project libbiosig 3.9.0 and Master Branch (35a819fa). A specially crafted MFER file can lead to arbitrary code execution. An attacker can provide a malicious file to trigger this vulnerability.This vulnerability manifests on line 9191 of biosig.c on the current master branch (35a819fa), when the Tag is 65: else if (tag==65) //0x41: patient event { // event table curPos += ifread(buf,1,len,hdr);

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 exists in libbiosig's MFER file parser at line 9191 of biosig.c. When processing tag 65 (patient event), the ifread() function copies data into a fixed-size stack buffer without validating that the input length (len) does not exceed the buffer size, allowing arbitrary code execution via specially crafted MFER files.

MitigationUpdate to a patched version of libbiosig when available. Until then, validate all MFER files in an isolated environment and disable MFER parsing if not required.

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:< 3.9.1

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 if libbiosig is installed
    Search for libbiosig library files (libbiosig.so, libbiosig.a, biosig.dll) in standard system paths such as /usr/lib/, /usr/local/lib/, or check package managers (dpkg -l | grep biosig, rpm -qa | grep biosig)
    Affected if libbiosig is present on the system
  2. Determine installed libbiosig version
    If library is found, run: nm libbiosig.so 2>/dev/null | grep -i version or check the library's metadata via file command, or query the package version from the package manager used in step 1
    Affected if The version is lower than 3.9.1 or cannot be determined (indicating it may be an unpatched build)
  3. Check if MFER parsing support is compiled in
    Examine the libbiosig build configuration: look for MFER-related symbols (nm libbiosig.so | grep -i mfer) or check for the presence of mfer.c in the source if you have access, or review compilation flags for ENABLE_MFER or similar defines
    Affected if MFER support is enabled (symbols found or MFER flag present in build)
  4. Identify processes or applications using libbiosig
    Search running processes and their loaded libraries: lsof +c 0 2>/dev/null | grep -E '(biosig|mfer)' or check application dependencies (ldd <application> | grep biosig)
    Affected if Any application loads libbiosig and processes MFER files
  5. Detect MFER file processing activity
    Monitor for MFER file access: use auditd rules (auditctl -w /path/to/files -k mfer) or check for .mfer file extensions in recent file access logs, or review application logs for MFER tag 65 processing
    Affected if MFER files are being opened or processed by libbiosig-based applications

You are affected if libbiosig version is below 3.9.1, MFER support is enabled in the library, and any application processes MFER files using the vulnerable code path at biosig.c line 9191.

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 3.9.1 or later
Fixed in 3.9.1
Interim mitigation

Update to a patched version of libbiosig when available. Until then, validate all MFER files in an isolated environment and disable MFER parsing if not required.

Recommended fix High confidence

libbiosig 3.9.1 or later

  1. Check the current version of libbiosig installed on the system using package manager commands or by examining the library files
  2. Upgrade libbiosig to version 3.9.1 or later. If using a package manager (e.g., apt, yum, brew), run the appropriate update command to install the latest version. For source installations, download libbiosig 3.9.1 or newer from the official repository and rebuild
  3. After upgrading, verify that the installed version is 3.9.1 or higher using the library's version check mechanism or by examining the binary
Caveat Review the release notes for 3.9.1 to check for any API changes or backward compatibility considerations before upgrading in production environments

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

Fix this in Libbiosig Scoped from the published advisory
  • Consultation2.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA4.0 h
20.0 hours of engineering $3,400
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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-2025-54491 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
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data