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NifiApplication · Apache

CVE-2020-9491

HIGH · 7.5 CVSS v3.1 Published 2020-10-01
Fix available
A fix is available. Upgrade to after 1.11.4 or later.
See remediation →
84/100
Remediation priority · High
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
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.

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

Apache NiFi 1.2.0-1.11.4 had inconsistent TLS enforcement: the UI/API properly required TLS v1.2, but intracluster communications (cluster request replication, Site-to-Site, load-balanced queues) allowed deprecated TLS v1.0/v1.1, exposing inter-node traffic to known protocol weaknesses.

MitigationConfigure all NiFi components to mandate TLS v1.2 or higher for all communications, including intracluster traffic, typically via nifi.properties SSL settings.

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
NifiApplication
Affected:>= 1.0.0, <= 1.11.4

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
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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 installed NiFi version
    Check the NiFi version by inspecting the nar.properties file in the NiFi installation directory (typically at $NIFI_HOME/conf/nar.properties) or by running 'ls -la' on the NiFi root directory to find the release manifest. Alternatively, access the NiFi UI and check the About section for the version number.
    Affected if The installed version is greater than or equal to 1.0.0 and less than or equal to 1.11.4. Versions outside this range or newer than 1.11.4 are not affected.
  2. Verify cluster communications are enabled
    Check nifi.properties for cluster-related settings: look for 'nifi.cluster.is.enabled=true' and 'nifi.cluster.node.address' or 'nifi.zookeeper.connect.string' entries. Also check for 'nifi.cluster.protocol.*' settings.
    Affected if NiFi is configured to run in cluster mode with cluster communications enabled. A standalone (non-clustered) installation is not affected by the intracluster vulnerability vector.
  3. Verify Site-to-Site is enabled
    Check nifi.properties for Site-to-Site configuration: look for 'nifi.s2s.enabled=true' and associated 'nifi.s2s.port' or 'nifi.remote.input.*' settings.
    Affected if Site-to-Site communication is enabled. If Site-to-Site is not configured or is disabled, that specific attack vector does not apply.
  4. Check TLS protocol configuration for cluster/Site-to-Site
    Examine nifi.properties for TLS settings controlling intracluster and Site-to-Site communications. Look for properties like 'nifi.cluster.protocol.communication.ssl.protocol', 'nifi.web.https.protocols', 'nifi.security.encryption.protocol', and any 'nifi.s2s.*.ssl.protocol' settings. Check if the configured protocol allows TLS v1.0 or v1.1.
    Affected if The TLS protocol configuration explicitly allows TLS v1.0 or TLS v1.1 (values such as 'TLS', 'TLSv1', 'TLSv1.1', or not restricting to 'TLSv1.2' minimum). If the configuration mandates TLSv1.2 or higher for all communications, the system is not vulnerable.

You are affected if NiFi version is between 1.0.0 and 1.11.4 AND cluster mode or Site-to-Site is enabled AND TLS configuration permits v1.0 or v1.1 for intracluster or Site-to-Site traffic.

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.

From vendor data
Upgrade available Upgrade to a release after 1.11.4
Interim mitigation

Configure all NiFi components to mandate TLS v1.2 or higher for all communications, including intracluster traffic, typically via nifi.properties SSL settings.

Fix this in Nifi Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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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-2020-9491 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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