CVE-2025-54481
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:
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 details traces, logs and code from the original report
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;CVSS
- Version: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Base score: 9.8
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days: 0.71%
- Percentile among all scored CVEs: 52
- Score date: 10/6/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
🎯 ATT&CK techniques
How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.
- Exploitation
T1190Exploit Public-Facing Applicationinitial access85 % - Primary impact
T1059Command and Scripting Interpreterexecution90 %
Buffer overflow en parser MFER (AV:N, AC:L, PR:N, UI:N) permite ejecución remota sin autenticación. Archivo MFER malicioso desencadena desbordamiento de pila causando ejecución de código arbitrario en línea 8744 de biosig.c.
Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.
🛡️ ATT&CK mitigations that cover these techniques
Affected technologies (1)
CWEs
- CWE-121
References
Raw JSON (NVD)
Show
{
"id": "CVE-2025-54481",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2025-54481",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "total"
}
],
"version": "2.0.3",
"timestamp": "2025-08-25T19:10:05.248134Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "talos-cna@cisco.com",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 9.8,
"attackVector": "NETWORK",
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.9,
"exploitabilityScore": 3.9
}
]
},
"affected": [
{
"source": "talos-cna@cisco.com",
"affectedData": [
{
"vendor": "The Biosig Project",
"product": "libbiosig",
"versions": [
{
"status": "affected",
"version": "3.9.0"
},
{
"status": "affected",
"version": "Master Branch (35a819fa)"
}
]
}
]
}
],
"published": "2025-08-25T14:15:33.700",
"references": [
{
"url": "https://talosintelligence.com/vulnerability_reports/TALOS-2025-2234",
"tags": [
"Exploit",
"Third Party Advisory"
],
"source": "talos-cna@cisco.com"
},
{
"url": "https://www.talosintelligence.com/vulnerability_reports/TALOS-2025-2234",
"source": "af854a3a-2127-422b-91ae-364da2661108"
}
],
"vulnStatus": "Modified",
"weaknesses": [
{
"type": "Secondary",
"source": "talos-cna@cisco.com",
"description": [
{
"lang": "en",
"value": "CWE-121"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "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:\r\n\r\n\t\t\t\telse if (tag==3) {\r\n\t\t\t\t\t// character code\r\n\t\t\t\t\tchar v[17];\t\t// [1]\r\n\t\t\t\t\tif (len>16) fprintf(stderr,\"Warning MFER tag2 incorrect length %i>16\\n\",len);\r\n\t\t\t\t\tcurPos += ifread(&v,1,len,hdr);\r\n\t\t\t\t\tv[len] = 0;\r\n\r\nIn 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."
},
{
"lang": "es",
"value": "Existe una vulnerabilidad de desbordamiento de búfer en la pila en la funcionalidad de análisis MFER de The Biosig Project libbiosig 3.9.0 y Master Branch (35a819fa). Un archivo MFER especialmente manipulado puede provocar la ejecución de código arbitrario. Un atacante puede proporcionar un archivo malicioso para activar esta vulnerabilidad. Esta vulnerabilidad se manifiesta en la línea 8744 de biosig.c en la rama maestra actual (35a819fa), cuando la etiqueta es 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; En este caso, el búfer desbordado es el recién declarado `v` \\[1\\] en lugar de `buf`. Dado que `v` tiene solo 17 bytes, valores mucho más pequeños de `len` (incluso aquellos codificados utilizando un solo octeto) pueden provocar un desbordamiento en esta ruta de código."
}
],
"lastModified": "2026-06-17T09:40:10.923",
"configurations": [
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:libbiosig_project:libbiosig:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "4893D615-FD95-4393-A5B0-E1BE19F180A6",
"versionEndExcluding": "3.9.1"
}
],
"operator": "OR"
}
]
}
],
"sourceIdentifier": "talos-cna@cisco.com"
}