dbcve.org
KylinApplication · Apache

CVE-2021-27738

HIGH · 7.5 CVSS v3.1 Published 2022-01-06
Fix available
A fix is available. Upgrade to 3.1.2 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
All request mappings in `StreamingCoordinatorController.java` handling `/kylin/api/streaming_coordinator/*` REST API endpoints did not include any security checks, which allowed an unauthenticated user to issue arbitrary requests, such as assigning/unassigning of streaming cubes, creation/modification and deletion of replica sets, to the Kylin Coordinator. For endpoints accepting node details in HTTP message body, unauthenticated (but limited) server-side request forgery (SSRF) can be achieved. This issue affects Apache Kylin Apache Kylin 3 versions prior to 3.1.2.

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 StreamingCoordinatorController.java exposes REST API endpoints under /kylin/api/streaming_coordinator/* without any authentication or authorization checks. This allows unauthenticated attackers to perform arbitrary operations including assigning/unassigning streaming cubes, creating/modifying/deleting replica sets, and potentially exploit SSRF via endpoints that accept node details in the HTTP body.

MitigationUpgrade to Apache Kylin 3.1.2 or later which includes proper authentication and authorization controls on the streaming coordinator endpoints. Alternatively, implement network-level restrictions to limit access to these administrative APIs.

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:>= 3.0.0, < 3.1.2

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
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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 Apache Kylin installation and version
    Locate the Kylin installation directory (commonly at $KYLIN_HOME or /opt/kylin) and check the version file (VERSION or kylin-common/pom.xml). Run 'kylin.sh version' or inspect build.properties for the version number.
    Affected if The installed version is >= 3.0.0 and < 3.1.2 (vulnerable versions)
  2. Verify streaming coordinator is enabled
    Check kylin.properties for 'kylin.stream.coordinator.enabled=true' or look for streaming coordinator configuration in conf/ or profiles/ directories.
    Affected if Streaming coordinator is enabled (the vulnerability only affects systems using the streaming coordinator feature)
  3. Confirm streaming coordinator REST endpoints are exposed
    Attempt to access http://<kylin-host>:<port>/kylin/api/streaming_coordinator/info or /replicaset endpoints. Check if these return HTTP 200 (exposed) rather than 401/403 (authenticated).
    Affected if The /kylin/api/streaming_coordinator/* endpoints are accessible without authentication (no login cookie or token required)
  4. Check if authentication is enforced on the Kylin API
    Review kylin.properties for 'kylin.security.enabled=true' and verify that the Kylin web UI or API requires login. Attempt an unauthenticated request to a protected endpoint like /kylin/api/user/authentication to confirm auth is required.
    Affected if Authentication is disabled or the streaming coordinator endpoints bypass existing authentication controls

A system is affected if it runs Apache Kylin version 3.0.0 through 3.1.1 with the streaming coordinator feature enabled and the /kylin/api/streaming_coordinator endpoints are accessible without authentication.

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 3.1.2 or later
Fixed in 3.1.2
Interim mitigation

Upgrade to Apache Kylin 3.1.2 or later which includes proper authentication and authorization controls on the streaming coordinator endpoints. Alternatively, implement network-level restrictions to limit access to these administrative APIs.

Recommended fix High confidence

3.1.2

  1. Upgrade Apache Kylin from version 3.0.0-3.1.1 to version 3.1.2 or later to address the unauthenticated SSRF vulnerability in the StreamingCoordinatorController

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 / QA2.0 h
18.0 hours of engineering $3,200
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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-2021-27738 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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