CVE-2020-9491
Status: ModifiedHigh (7.5)—
In Apache NiFi 1.2.0 to 1.11.4, the NiFi UI and API were protected by mandating TLS v1.2, as well as listening connections established by processors like ListenHTTP, HandleHttpRequest, etc. However intracluster communication such as cluster request replication, Site-to-Site, and load balanced queues continued to support TLS v1.0 or v1.1.
CVSS
- Version: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Base score: 7.5
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days: 2.87%
- Percentile among all scored CVEs: 86
- Score date: 10/10/2026
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).
Affected technologies (1)
CWEs
- CWE-327
References
- https://lists.apache.org/thread.html/r2d9c21f9ec35d66f2bb42f8abe876dabd786166b6284e9a33582c718%40%3Ccommits.nifi.apache.org%3E
- https://lists.apache.org/thread.html/re48582efe2ac973f8cff55c8b346825cb491c71935e15ab2d61ef3bf%40%3Ccommits.nifi.apache.org%3E
- https://nifi.apache.org/security#CVE-2020-9491
- https://lists.apache.org/thread.html/r2d9c21f9ec35d66f2bb42f8abe876dabd786166b6284e9a33582c718%40%3Ccommits.nifi.apache.org%3E
- https://lists.apache.org/thread.html/re48582efe2ac973f8cff55c8b346825cb491c71935e15ab2d61ef3bf%40%3Ccommits.nifi.apache.org%3E
- https://nifi.apache.org/security#CVE-2020-9491
Raw JSON (NVD)
Show
{
"id": "CVE-2020-9491",
"cveTags": [],
"metrics": {
"cvssMetricV2": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"version": "2.0",
"baseScore": 5,
"accessVector": "NETWORK",
"vectorString": "AV:N/AC:L/Au:N/C:P/I:N/A:N",
"authentication": "NONE",
"integrityImpact": "NONE",
"accessComplexity": "LOW",
"availabilityImpact": "NONE",
"confidentialityImpact": "PARTIAL"
},
"acInsufInfo": false,
"impactScore": 2.9,
"baseSeverity": "MEDIUM",
"obtainAllPrivilege": false,
"exploitabilityScore": 10,
"obtainUserPrivilege": false,
"obtainOtherPrivilege": false,
"userInteractionRequired": false
}
],
"cvssMetricV31": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 7.5,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "NONE",
"privilegesRequired": "NONE",
"confidentialityImpact": "HIGH"
},
"impactScore": 3.6,
"exploitabilityScore": 3.9
}
]
},
"affected": [
{
"source": "security@apache.org",
"affectedData": [
{
"vendor": "n/a",
"product": "Apache NiFi",
"versions": [
{
"status": "affected",
"version": "Apache NiFi 1.2.0 to 1.11.4"
}
]
}
]
}
],
"published": "2020-10-01T20:15:14.330",
"references": [
{
"url": "https://lists.apache.org/thread.html/r2d9c21f9ec35d66f2bb42f8abe876dabd786166b6284e9a33582c718%40%3Ccommits.nifi.apache.org%3E",
"source": "security@apache.org"
},
{
"url": "https://lists.apache.org/thread.html/re48582efe2ac973f8cff55c8b346825cb491c71935e15ab2d61ef3bf%40%3Ccommits.nifi.apache.org%3E",
"source": "security@apache.org"
},
{
"url": "https://nifi.apache.org/security#CVE-2020-9491",
"tags": [
"Vendor Advisory"
],
"source": "security@apache.org"
},
{
"url": "https://lists.apache.org/thread.html/r2d9c21f9ec35d66f2bb42f8abe876dabd786166b6284e9a33582c718%40%3Ccommits.nifi.apache.org%3E",
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://lists.apache.org/thread.html/re48582efe2ac973f8cff55c8b346825cb491c71935e15ab2d61ef3bf%40%3Ccommits.nifi.apache.org%3E",
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://nifi.apache.org/security#CVE-2020-9491",
"tags": [
"Vendor Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
}
],
"vulnStatus": "Modified",
"weaknesses": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"description": [
{
"lang": "en",
"value": "CWE-327"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In Apache NiFi 1.2.0 to 1.11.4, the NiFi UI and API were protected by mandating TLS v1.2, as well as listening connections established by processors like ListenHTTP, HandleHttpRequest, etc. However intracluster communication such as cluster request replication, Site-to-Site, and load balanced queues continued to support TLS v1.0 or v1.1."
},
{
"lang": "es",
"value": "En Apache NiFi versiones 1.2.0 hasta 1.11.4, la Interfaz de Usuario y la API de NiFi estaban protegidas al exigir TLS versión v1.2, así como las conexiones de escucha establecidas por procesadores como ListenHTTP, HandleHttpRequest, etc. Sin embargo, la comunicación intracluster, como la replicación de peticiones de clúster, Site -to-Site, y las colas de balanceo de carga continuaban admitiendo TLS versión v1.0 o v1.1"
}
],
"lastModified": "2026-06-17T03:28:03.430",
"configurations": [
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:apache:nifi:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "43022122-9397-48D7-BD86-925042103633",
"versionEndIncluding": "1.11.4",
"versionStartIncluding": "1.0.0"
}
],
"operator": "OR"
}
]
}
],
"sourceIdentifier": "security@apache.org"
}