dbcve.org
DruidApplication · Apache

CVE-2021-26919

HIGH · 8.8 CVSS v3.1 Published 2021-03-30
Fix available
A fix is available. Upgrade to 0.20.2 or later.
See remediation →
94/100
Remediation priority · Urgent
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
Apache Druid allows users to read data from other database systems using JDBC. This functionality is to allow trusted users with the proper permissions to set up lookups or submit ingestion tasks. The MySQL JDBC driver supports certain properties, which, if left unmitigated, can allow an attacker to execute arbitrary code from a hacker-controlled malicious MySQL server within Druid server processes. This issue was addressed in Apache Druid 0.20.2

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

Apache Druid's JDBC functionality allows users to read data from external databases for lookups or ingestion tasks. The MySQL JDBC driver supports certain properties that, when connecting to a malicious MySQL server controlled by an attacker, can allow arbitrary code execution within the Druid server process. An attacker would need to trick a privileged user (with JDBC permissions) into connecting to their controlled MySQL server.

MitigationUpgrade to Apache Druid 0.20.2 or later. Additionally, restrict JDBC lookup/ingestion permissions to minimal trusted users and implement network controls to prevent Druid from connecting to untrusted database servers.

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
DruidApplication
Affected:< 0.20.2

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

CVSS:3.1/AV:N/AC:L/PR:L/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. Determine installed Apache Druid version
    Check the Druid version file or console. Common locations include the release metadata file or the Druid console (typically port 8888). Compare your version against the affected range: versions prior to 0.20.2 are vulnerable.
    Affected if Your Druid version is lower than 0.20.2 and you use JDBC functionality.
  2. Identify if JDBC lookup or ingestion is enabled
    Review your Druid configuration for lookup definitions or ingestion specs that use the JDBC lookup extension or JDBC-based data sources. Check for 'jdbc' type entries in your lookup configuration or ingestion JSON specs.
    Affected if JDBC lookups or JDBC-based ingestion tasks are configured and actively in use.
  3. Confirm MySQL JDBC driver usage
    Examine your Druid classpath or extension directory for the presence of the MySQL JDBC driver (mysql-connector-java or similar). Also review your JDBC connection strings to identify mysql:// URLs.
    Affected if Your JDBC connections target MySQL databases using the vulnerable driver properties.
  4. Review JDBC permissions assignment
    Audit which users or roles have permissions to configure JDBC lookups or JDBC ingestion tasks. Check your authentication and authorization configuration to identify users with lookup or ingestion write access.
    Affected if Privileged users with JDBC configuration permissions could be tricked into connecting to a malicious MySQL server.

You are affected if your Apache Druid installation is version 0.20.2 or earlier AND you have JDBC lookups or JDBC-based ingestion configured, allowing a privileged user to connect to MySQL databases.

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 0.20.2 or later
Fixed in 0.20.2
Interim mitigation

Upgrade to Apache Druid 0.20.2 or later. Additionally, restrict JDBC lookup/ingestion permissions to minimal trusted users and implement network controls to prevent Druid from connecting to untrusted database servers.

Recommended fix High confidence

Apache Druid 0.20.2 or later

  1. Upgrade Apache Druid from any version below 0.20.2 to version 0.20.2 or later
  2. Test the upgrade in a non-production environment first
  3. Verify that JDBC lookup and ingestion tasks function correctly after the upgrade
  4. Review and validate JDBC connection configurations to ensure only trusted MySQL servers are accessed

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

Fix this in Druid Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
16.0 hours of engineering $2,760
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,416.

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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-2021-26919 in production — separate from our analysis above.

No notes yet

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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
  • No spam, self-promotion, credentials, or personal data