Summary
Druid ingestion system Authenticated users can read data from other sources than intended
In the Druid ingestion system, the InputSource is used for reading data from a certain data source. However, the HTTP InputSource allows authenticated users to read data from other sources than intended, such as the local file system, with the privileges of the Druid server process. This is not an elevation of privilege when users access Druid directly, since Druid also provides the Local InputSource, which allows the same level of access. But it is problematic when users interact with Druid indirectly through an application that allows users to specify the HTTP InputSource, but not the Local InputSource. In this case, users could bypass the application-level restriction by passing a file URL to the HTTP InputSource.
Impact
The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.
CVE-2021-26920 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.21.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2021-26920? CVE-2021-26920 is a medium-severity incorrect authorization vulnerability in org.apache.druid:druid-core (maven), affecting versions < 0.21.0. It is fixed in 0.21.0. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
- How severe is CVE-2021-26920? CVE-2021-26920 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of org.apache.druid:druid-core are affected by CVE-2021-26920? org.apache.druid:druid-core (maven) versions < 0.21.0 is affected.
- Is there a fix for CVE-2021-26920? Yes. CVE-2021-26920 is fixed in 0.21.0. Upgrade to this version or later.
- Is CVE-2021-26920 exploitable, and should I be worried? Whether CVE-2021-26920 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2021-26920 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2021-26920? Upgrade
org.apache.druid:druid-coreto 0.21.0 or later.