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LibbiosigApplication · Libbiosig Project

CVE-2025-54493

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 9184 of biosig.c on the current master branch (35a819fa), when the Tag is 131: else if (tag==131) //0x83 { // Patient Age if (len!=7) fprintf(stderr,"Warning MFER tag131 incorrect length %i!=7\n",len); 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 · high confidence

A stack-based buffer overflow exists in libbiosig's MFER file parser at line 9184 of biosig.c. When processing Tag 131 (Patient Age), the code reads 'len' bytes into a fixed-size buffer 'buf' without validating that 'len' does not exceed the buffer's capacity. An attacker can provide a specially crafted MFER file with a length value exceeding the buffer size to overflow the stack and achieve arbitrary code execution.

MitigationImplement strict bounds checking to validate that 'len' does not exceed the buffer size before calling ifread(). Additionally, audit the entire MFER parser and related parsing code for similar unchecked buffer operations. Apply any available vendor patches for libbiosig.

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 libbiosig installation and version
    Locate the libbiosig library on the system (commonly installed as libbiosig.so or biosig.lib in system or application directories) and query its version using tools like 'ldd', 'dpkg -l', 'rpm -qi', or checking the library's metadata
    Affected if libbiosig is installed and its version is lower than 3.9.1
  2. Verify MFER file processing capability
    Check if the installed libbiosig build includes MFER parser support by examining compiled symbols (e.g., 'nm libbiosig.so | grep -i mfer') or reviewing build configuration files
    Affected if MFER parser support is compiled into the library
  3. Confirm vulnerable code path exists
    If source code is available, inspect biosig.c around line 9184 for the MFER Tag 131 (Patient Age) parsing logic and verify if the buffer 'buf' lacks bounds checking before the ifread() call
    Affected if The vulnerable code path in biosig.c line 9184 is present without bounds validation on the 'len' parameter
  4. Check for MFER file input processing
    Audit any applications or scripts that use libbiosig to process input files, specifically looking for MFER file format handling (file extension .mfer or MIME type 'application/x-mfer')
    Affected if Any application or tool processes MFER files using the affected libbiosig library

A system is affected if libbiosig version is below 3.9.1 and MFER file parsing functionality is actively used to process MFER files with the vulnerable code present.

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

Implement strict bounds checking to validate that 'len' does not exceed the buffer size before calling ifread(). Additionally, audit the entire MFER parser and related parsing code for similar unchecked buffer operations. Apply any available vendor patches for libbiosig.

Recommended fix High confidence

libbiosig 3.9.1

  1. Identify all systems or applications that use libbiosig library
  2. Verify the current installed version of libbiosig (likely through package manager or build system)
  3. If version is below 3.9.1, obtain and install libbiosig version 3.9.1 or later
  4. Rebuild or recompile any applications that link against libbiosig to use the updated library
  5. Test the updated system to ensure the MFER parsing functionality works correctly
  6. Consider implementing additional input validation for MFER files at the application layer as a defense-in-depth measure
Caveat None documented in the provided information; minor version upgrade within same major version typically has minimal breaking changes

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 / QA3.0 h
21.0 hours of engineering $3,680
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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-2025-54493 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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