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LibbiosigApplication · Libbiosig Project

CVE-2025-54487

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 8842 of biosig.c on the current master branch (35a819fa), when the Tag is 12: else if (tag==12) //0x0C { // sampling resolution if (len>6) fprintf(stderr,"Warning MFER tag12 incorrect length %i>6\n",len); val32 = 0; int8_t v8; curPos += ifread(&UnitCode,1,1,hdr); curPos += ifread(&v8,1,1,hdr); curPos += ifread(buf,1,len-2,hdr); In addition to values of `len` greater than 130 triggering a buffer overflow, a value of `len` smaller than 2 will also trigger a buffer overflow due to an integer underflow when computing `len-2` in this code path.

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 in libbiosig's MFER file parser (biosig.c:8842) occurs when parsing Tag 12 (sampling resolution) due to missing bounds validation on the `len` field. When `len > 130` or `len < 2`, the read operation `curPos += ifread(buf,1,len-2,hdr)` writes beyond the buffer boundaries, allowing arbitrary code execution.

MitigationUpdate to a patched version of libbiosig when available; otherwise, implement bounds checking on the `len` value before the ifread operation and add integer underflow protection for the `len-2` calculation.

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. Check if libbiosig library is installed
    Search for libbiosig shared library on the system using package manager or file system search (e.g., dpkg -l, rpm -qa, or find /usr/lib -name '*biosig*')
    Affected if The libbiosig library is found on the system
  2. Identify the installed libbiosig version
    Query the library version through package manager, or check library file version metadata, or use 'strings' on the library to look for version strings
    Affected if The version is lower than 3.9.1 (e.g., 3.9.0 or earlier)
  3. Verify if MFER file parsing support is enabled
    Check if libbiosig was compiled with MFER support (check compile-time flags, or look for MFER-related functions in the binary); also check if any applications on the system are configured to process MFER files
    Affected if MFER parsing is enabled and applications process .mfer files
  4. Inspect MFER parsing code path for vulnerable condition
    If source code is available, examine biosig.c around line 8842 for Tag 12 parsing; verify if bounds checking on 'len' field exists before the ifread call
    Affected if Bounds validation on 'len' is missing and len > 130 or len < 2 can occur during MFER file processing

You are affected if libbiosig version is below 3.9.1 AND your system processes MFER files with the vulnerable Tag 12 parsing code path.

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; otherwise, implement bounds checking on the `len` value before the ifread operation and add integer underflow protection for the `len-2` calculation.

Recommended fix High confidence

libbiosig 3.9.1

  1. Download libbiosig version 3.9.1 or later from the official Biosig Project repository or source distribution
  2. Compile and install the updated libbiosig library (3.9.1 or later)
  3. Verify the installed version by checking the library version or using pkg-config
  4. Recompile any applications that link against libbiosig to ensure they use the updated library
  5. Test MFER file parsing functionality to confirm the vulnerability is resolved

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

Fix this in Libbiosig Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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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-2025-54487 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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