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KylinApplication · Apache

CVE-2021-45456

CRITICAL · 9.8 CVSS v3.1 Published 2022-01-06
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
High EPSS 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
Apache kylin checks the legitimacy of the project before executing some commands with the project name passed in by the user. There is a mismatch between what is being checked and what is being used as the shell command argument in DiagnosisService. This may cause an illegal project name to pass the check and perform the following steps, resulting in a command injection vulnerability. This issue affects Apache Kylin 4.0.0.

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

Command injection vulnerability in Apache Kylin's DiagnosisService where project name validation logic checks one value but a different (user-controlled) value is used in shell command execution. This validation mismatch allows attackers to bypass the legitimacy check and inject arbitrary shell commands via specially crafted project names.

MitigationUpgrade to a patched version of Apache Kylin; if immediate patching is not feasible, restrict or disable the diagnosis functionality and implement strict input validation with allowlist filtering on project names before shell command execution.

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
KylinApplication
Affected:= 4.0.0

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
High
Availability
High

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

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 Apache Kylin version
    Check the installed version by accessing the Kylin web UI About page, or inspect version files in the Kylin installation directory. Common locations include the build timestamp file or the kylin.properties configuration.
    Affected if The installed version is exactly 4.0.0.
  2. Verify DiagnosisService endpoint accessibility
    Identify if the DiagnosisService API endpoints are exposed and accessible. Check Kylin's web.xml or Spring configuration files for diagnosis-related servlet mappings, typically under /kylin/api/* or /diagnosis/* paths.
    Affected if DiagnosisService endpoints are reachable without additional authentication or with weak authentication controls.
  3. Check project name input handling
    Review how project names are processed in the DiagnosisService code. The vulnerability stems from a validation mismatch where one project name is validated but a different user-controlled value is used in shell execution. Inspect the DiagnosisService Java code for the diagnosisAction method and how project parameters are extracted and passed to runtime execution.
    Affected if Project names are passed directly to Runtime.exec() or similar shell execution methods without proper sanitization.
  4. Audit project creation privileges
    Determine which users can create or modify project names in Kylin. Check Kylin's ACL configuration and determine if untrusted users have project creation permissions.
    Affected if Users with limited privileges can create projects with arbitrary names.

You are affected if running Apache Kylin 4.0.0 with the DiagnosisService accessible to users who can create projects with arbitrary names that get shell-executed without proper validation.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to a patched version of Apache Kylin; if immediate patching is not feasible, restrict or disable the diagnosis functionality and implement strict input validation with allowlist filtering on project names before shell command execution.

Recommended fix High confidence

Apache Kylin 4.0.1 or later

  1. 1. Back up the current Apache Kylin 4.0.0 configuration, metadata, and data directories.
  2. 2. Stop the Kylin service to prevent any active sessions during upgrade.
  3. 3. Download Apache Kylin 4.0.1 (or the latest stable 4.x release) from the official Apache Kylin repository.
  4. 4. Install the new version following the standard upgrade documentation, preserving the backed-up configuration.
  5. 5. Validate the upgrade by checking that DiagnosisService properly sanitizes project name inputs.
  6. 6. Restart the Kylin service and verify normal operation.
Caveat Review release notes for any configuration changes or migration steps required between 4.0.0 and 4.0.1

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

Fix this in Kylin Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA3.0 h
19.0 hours of engineering $3,380
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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-2021-45456 in production — separate from our analysis above.

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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
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