CVE-2020-13365
Certain Zyxel products have a locally accessible binary that allows a non-root user to generate a password for an undocumented user account that can be used for a TELNET session as root. This affects NAS520 V5.21(AASZ.4)C0, V5.21(AASZ.0)C0, V5.11(AASZ.3)C0, and V5.11(AASZ.0)C0; NAS542 V5.11(ABAG.0)C0, V5.20(ABAG.1)C0, and V5.21(ABAG.3)C0; NSA325 v2_V4.81(AALS.0)C0 and V4.81(AAAJ.1)C0; NSA310 4.22(AFK.0)C0 and 4.22(AFK.1)C0; NAS326 V5.21(AAZF.8)C0, V5.11(AAZF.4)C0, V5.11(AAZF.2)C0, and V5.11(AAZF.3)C0; NSA310S V4.75(AALH.2)C0; NSA320S V4.75(AANV.2)C0 and V4.75(AANV.1)C0; NSA221 V4.41(AFM.1)C0; and NAS540 V5.21(AATB.5)C0 and V5.21(AATB.3)C0.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Puntuación base: 8.8
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.97%
- Percentil entre todas las CVEs puntuadas: 61
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (4)
CWE
- CWE-287
Referencias
- https://www.zyxel.com/support/Zyxel-security-advisory-for-NAS-remote-access-vulnerability.shtml
- https://www.zyxel.com/us/en/support/security_advisories.shtml
- https://www.zyxel.com/support/Zyxel-security-advisory-for-NAS-remote-access-vulnerability.shtml
- https://www.zyxel.com/us/en/support/security_advisories.shtml
JSON original (NVD)
Mostrar
{
"id": "CVE-2020-13365",
"cveTags": [],
"metrics": {
"cvssMetricV2": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"version": "2.0",
"baseScore": 9,
"accessVector": "NETWORK",
"vectorString": "AV:N/AC:L/Au:S/C:C/I:C/A:C",
"authentication": "SINGLE",
"integrityImpact": "COMPLETE",
"accessComplexity": "LOW",
"availabilityImpact": "COMPLETE",
"confidentialityImpact": "COMPLETE"
},
"acInsufInfo": false,
"impactScore": 10,
"baseSeverity": "HIGH",
"obtainAllPrivilege": false,
"exploitabilityScore": 8,
"obtainUserPrivilege": false,
"obtainOtherPrivilege": false,
"userInteractionRequired": false
}
],
"cvssMetricV30": [
{
"type": "Secondary",
"source": "cve@mitre.org",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.0",
"baseScore": 8.4,
"attackVector": "LOCAL",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.0/AV:L/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": 2.5
}
],
"cvssMetricV31": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 8.8,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "LOW",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.9,
"exploitabilityScore": 2.8
}
]
},
"affected": [
{
"source": "cve@mitre.org",
"affectedData": [
{
"vendor": "n/a",
"product": "n/a",
"versions": [
{
"status": "affected",
"version": "n/a"
}
]
}
]
}
],
"published": "2020-08-06T17:15:10.957",
"references": [
{
"url": "https://www.zyxel.com/support/Zyxel-security-advisory-for-NAS-remote-access-vulnerability.shtml",
"tags": [
"Vendor Advisory"
],
"source": "cve@mitre.org"
},
{
"url": "https://www.zyxel.com/us/en/support/security_advisories.shtml",
"tags": [
"Vendor Advisory"
],
"source": "cve@mitre.org"
},
{
"url": "https://www.zyxel.com/support/Zyxel-security-advisory-for-NAS-remote-access-vulnerability.shtml",
"tags": [
"Vendor Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://www.zyxel.com/us/en/support/security_advisories.shtml",
"tags": [
"Vendor Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
}
],
"vulnStatus": "Modified",
"weaknesses": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"description": [
{
"lang": "en",
"value": "CWE-287"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Certain Zyxel products have a locally accessible binary that allows a non-root user to generate a password for an undocumented user account that can be used for a TELNET session as root. This affects NAS520 V5.21(AASZ.4)C0, V5.21(AASZ.0)C0, V5.11(AASZ.3)C0, and V5.11(AASZ.0)C0; NAS542 V5.11(ABAG.0)C0, V5.20(ABAG.1)C0, and V5.21(ABAG.3)C0; NSA325 v2_V4.81(AALS.0)C0 and V4.81(AAAJ.1)C0; NSA310 4.22(AFK.0)C0 and 4.22(AFK.1)C0; NAS326 V5.21(AAZF.8)C0, V5.11(AAZF.4)C0, V5.11(AAZF.2)C0, and V5.11(AAZF.3)C0; NSA310S V4.75(AALH.2)C0; NSA320S V4.75(AANV.2)C0 and V4.75(AANV.1)C0; NSA221 V4.41(AFM.1)C0; and NAS540 V5.21(AATB.5)C0 and V5.21(AATB.3)C0."
},
{
"lang": "es",
"value": "Determinados productos Zyxel tienen un binario accesible localmente que permite a un usuario no root generar una contraseña para una cuenta de usuario no documentada que puede ser usada para una sesión de TELNET como root. Esto afecta a NAS520 V5.21(AASZ.4)C0, V5.21(AASZ.0)C0, V5.11(AASZ.3)C0, y V5.11(AASZ.0)C0; NAS542 V5.11(ABAG.0)C0, V5.20(ABAG.1)C0, y V5.21(ABAG.3)C0; NSA325 v2_V4.81(AALS.0)C0 y V4.81(AAAJ.1)C0; NSA310 4.22(AFK.0)C0 y 4.22(AFK.1)C0; NAS326 V5.21(AAZF.8)C0, V5.11(AAZF.4)C0, V5.11(AAZF.2)C0, y V5.11(AAZF.3)C0; NSA310S V4.75(AALH.2)C0; NSA320S V4.75(AANV.2)C0 y V4.75(AANV.1)C0; NSA221 V4.41(AFM.1)C0; y NAS540 V5.21(AATB.5)C0 y V5.21(AATB.3)C0"
}
],
"lastModified": "2026-06-17T02:53:02.053",
"configurations": [
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:o:zyxel:nas326_firmware:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "B045EF5D-B584-4DAA-B0EF-149310C61AC1",
"versionEndExcluding": "v5.21\\(aazf.9\\)c0"
}
],
"operator": "OR"
},
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:h:zyxel:nas326:-:*:*:*:*:*:*:*",
"vulnerable": false,
"matchCriteriaId": "E0A01B19-4A91-4FBC-8447-2E854346DAC5"
}
],
"operator": "OR"
}
],
"operator": "AND"
},
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:o:zyxel:nas520_firmware:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "D88E8EAE-2492-421F-A904-CE167C0C6B61",
"versionEndExcluding": "v5.21\\(aasz.5\\)c0"
}
],
"operator": "OR"
},
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:h:zyxel:nas520:-:*:*:*:*:*:*:*",
"vulnerable": false,
"matchCriteriaId": "07B2BA3D-40F0-4D59-8838-B226FAABF27E"
}
],
"operator": "OR"
}
],
"operator": "AND"
},
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:o:zyxel:nas540_firmware:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "8D4A8264-3806-47C1-BDCB-04C569BC74CD",
"versionEndExcluding": "v5.21\\(aatb.6\\)c0"
}
],
"operator": "OR"
},
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:h:zyxel:nas540:-:*:*:*:*:*:*:*",
"vulnerable": false,
"matchCriteriaId": "B2F7264C-D32A-4EE9-BADC-78518D762BCA"
}
],
"operator": "OR"
}
],
"operator": "AND"
},
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:o:zyxel:nas542_firmware:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "23F5B87E-5526-4CDD-8F96-D78C00B7B490",
"versionEndExcluding": "v5.21\\(abag.6\\)c0"
}
],
"operator": "OR"
},
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:h:zyxel:nas542:-:*:*:*:*:*:*:*",
"vulnerable": false,
"matchCriteriaId": "31C4DD0F-28D0-4BF7-897B-5EEC32AA7277"
}
],
"operator": "OR"
}
],
"operator": "AND"
}
],
"sourceIdentifier": "cve@mitre.org"
}