CVE-2021-26920 Apache Druid: The HTTP inputSource allows authenticated users to read data from other sources than intended
Authenticated users can bypass application restrictions to read local files via HTTP input source, exposing sensitive data.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-26920?
CVE-2021-26920 is a medium-severity server-side request forgery vulnerability in Apache Druid, published on 2 Jul 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-610
Which versions are affected by CVE-2021-26920?
It affects 1 product.
Products include Apache Druid.
How do I fix CVE-2021-26920?
Upgrade to a fixed version.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2021-26920 being exploited?
There is no known exploitation of CVE-2021-26920 in the wild and no public exploit code.
Other vulnerabilities in Apache Druid
- CVE-2026-23906 Apache Druid: Authentication Bypass via LDAP Anonymous Bind
- CVE-2025-59390 Apache Druid: Kerberos authenticaton chooses a cryptographically unsecure secret if not configured explicitly.
- CVE-2021-26919 Apache Druid Authenticated users can execute arbitrary code from malicious MySQL database systems.
- CVE-2021-25646 Authenticated users can override system configurations in their requests which allows them to execute arbitrary code.
- CVE-2024-45537 Apache Druid: Users can provide MySQL JDBC properties not on allow list