CVE-2021-26920: Apache Druid: The HTTP inputSource allows authenticated users to read data from other sources than intended
- Is it exploited?
Reported, not confirmed by CISA. VulnCheck KEV lists it as exploited in the wild. CISA has not added it to its Known Exploited Vulnerabilities catalog as of .
VulnCheck KEV lists it since .
- How likely is exploitation in the next 30 days?
- 9.5%
EPSS score, percentile 95.4 of all scored records. A probability estimated by FIRST, not a report of exploitation.
- How severe?
- Not scored
The CVE record carries no CVSS score.
- What should I do?
CISA has set no required action, because the vulnerability is not in KEV.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- Apache Druid through 0.20.2
Source: CISA KEV 2026.10.29, as of ; VulnCheck KEV, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.
Description
Apache Druid: The HTTP inputSource allows authenticated users to 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.
Source: CVE List, as of . About the data.
What to do
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Workaround (from the CVE record)
Users can avoid the issue by upgrading to 0.21.0 or a higher version. In an earlier version than 0.21.0, when the user application wants to restrict the access to the local file system, it should disallow all InputSources that can read local files, that is the Local, HTTP, and HDFS InputSources.
This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.
Affected products and versions
Versions by product, as listed in the CVE record (1 product)
| Status | Versions |
|---|---|
| Affected | Apache Druid through 0.20.2 |
Source: CVE List, as of . About the data.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| CVE record last updated |
References
6
- lists.apache.org
- [oss-security] 20210702 CVE-2021-26920: Apache Druid: The HTTP inputSource allows authenticated users to read data from other sources than intended
- [announce] 20210701 CVE-2021-26920: Apache Druid: The HTTP inputSource allows authenticated users to read data from other sources than intended
- [druid-dev] 20210923 CVE-2021-36749: Apache Druid: The HTTP inputSource allows authenticated users to read data from other sources than intended (incomplete fi…
- [oss-security] 20210923 CVE-2021-36749: Apache Druid: The HTTP inputSource allows authenticated users to read data from other sources than intended (incomplete…
- [announce] 20210923 CVE-2021-36749: Apache Druid: The HTTP inputSource allows authenticated users to read data from other sources than intended (incomplete fix…
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