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LibbiosigApplication · Libbiosig Project

CVE-2025-54481

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 8744 of biosig.c on the current master branch (35a819fa), when the Tag is 3: else if (tag==3) { // character code char v[17]; // [1] if (len>16) fprintf(stderr,"Warning MFER tag2 incorrect length %i>16\n",len); curPos += ifread(&v,1,len,hdr); v[len] = 0; In this case, the overflowed buffer is the newly-declared `v` \[1\] instead of `buf`. Since `v` is only 17 bytes large, much smaller values of `len` (even those encoded using a single octet) can trigger an overflow 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

Stack-based buffer overflow in libbiosig's MFER file parser when processing Tag==3. A fixed-size 17-byte stack buffer 'char v[17]' is overflowed by writing v[len]=0 without validating that len<=16, allowing arbitrary code execution via specially crafted MFER files.

MitigationUpdate libbiosig to patched version; implement bounds checking before buffer access and validate MFER input length fields before use.

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 (e.g., libbiosig.so, libbiosig.a, biosig.dll) in system library directories (/usr/lib, /usr/local/lib) or application bund directories. Also check package managers (dpkg -l, rpm -qa) for libbiosig packages.
    Affected if libbiosig library is present on the system
  2. Check installed libbiosig version
    If libbiosig is found, determine its version. For dynamic libraries, use 'strings' on the library file and search for version strings, or use 'ldd' with an application that links to it. Check any version documentation or headers in the library.
    Affected if Installed version is lower than 3.9.1
  3. Verify MFER file parsing is in use
    Check if there are MFER files (.mfer extension) being processed, or if applications using libbiosig have MFER support enabled. Search for 'mfer' in process command lines, configuration files, or application logs.
    Affected if MFER files are being parsed or MFER support is enabled in applications using libbiosig
  4. Inspect MFER parser code path for Tag==3
    If source code is available, review the MFER parsing implementation in libbiosig for the vulnerable code path handling Tag==3 and the 'char v[17]' buffer. Look for missing bounds validation before the v[len]=0 write.
    Affected if Code contains the vulnerable MFER Tag==3 parser without length validation before buffer write

A user is affected if libbiosig version < 3.9.1 is installed AND MFER file parsing with Tag==3 handling is actively used in their environment.

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 libbiosig to patched version; implement bounds checking before buffer access and validate MFER input length fields before use.

Recommended fix High confidence

libbiosig 3.9.1

  1. Upgrade libbiosig to version 3.9.1 or later from the official source repository
  2. Recompile and rebuild any applications or libraries that link against libbiosig
  3. Verify the upgrade by testing MFER file parsing functionality
  4. Check application logs for any warnings related to MFER tag2 length during testing

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

Fix this in Libbiosig Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA3.0 h
18.0 hours of engineering $3,060
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,896.

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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-2025-54481 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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