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NifiApplication · Apache

CVE-2021-44145

MEDIUM · 6.5 CVSS v3.1 Published 2021-12-17
Fix available
A fix is available. Upgrade to 1.15.1 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable 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 the TransformXML processor of Apache NiFi before 1.15.1 an authenticated user could configure an XSLT file which, if it included malicious external entity calls, may reveal sensitive information.

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

The TransformXML processor in Apache NiFi before 1.15.1 contains an XML External Entity (XXE) vulnerability. An authenticated user with permissions to configure the processor can supply a malicious XSLT file containing external entity declarations that cause the processor to read and expose sensitive files from the NiFi server's filesystem.

MitigationUpgrade Apache NiFi to version 1.15.1 or later which disables external entity processing. Until upgrade is possible, restrict TransformXML processor usage to only highly trusted authenticated users and consider disabling the processor entirely.

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:>= 0.1.0, < 1.15.1

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/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 TransformXML processor usage
    In NiFi UI, search for TransformXML processors in the component palette or inspect the flow.xml.gz for instances of the TransformXML processor type.
    Affected if Any TransformXML processor is configured in the NiFi flow
  2. Check installed NiFi version
    Locate the NiFi installation directory and check the LICENSE file or run 'nifi.sh version' command. Alternatively, the version is displayed on the NiFi UI login page or in the About dialog (Help > About).
    Affected if The installed version is less than 1.15.1 (versions 0.1.0 through 1.15.0 are affected)
  3. Review TransformXML processor permissions
    In NiFi UI, right-click each TransformXML processor and select 'View Details' > 'Permissions' tab. Check which users or groups have ability to configure the processor. Cross-reference with user access policies in the Global Menu > Users and Policies.
    Affected if Users other than highly trusted administrators can configure the TransformXML processor

You are affected if NiFi version is below 1.15.1 AND the TransformXML processor is accessible to users who are not highly trusted administrators.

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 1.15.1 or later
Fixed in 1.15.1
Interim mitigation

Upgrade Apache NiFi to version 1.15.1 or later which disables external entity processing. Until upgrade is possible, restrict TransformXML processor usage to only highly trusted authenticated users and consider disabling the processor entirely.

Recommended fix High confidence

1.15.1

  1. Stop the current Apache NiFi service
  2. Back up the entire NiFi installation directory (including flow.xml.gz and any custom configurations)
  3. Download Apache NiFi 1.15.1 or later from the official Apache NiFi download page at nifi.apache.org
  4. Install the new NiFi version to the desired location
  5. Copy the backed-up flow.xml.gz and any custom configuration files to the new installation
  6. Start the NiFi service
  7. Log in and verify the TransformXML processor functions correctly with the upgrade
Caveat Review the Apache NiFi 1.15.1 release notes for any processor behavior changes or configuration updates before deploying to production

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

Fix this in Nifi Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,280
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,648.

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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-2021-44145 in production — separate from our analysis above.

No notes yet

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What this is

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