CVE-2021-36749

MEDIUM EXPLOITED IN THE WILD NUCLEI

Apache Druid < 0.22.0 - Authenticated Arbitrary File Read via HTTP InputSource

Title source: llm
STIX 2.1

Exploitation Summary

CVE-2021-36749 has been observed exploited in the wild (reported by VulnCheck KEV, InTheWild.io). EIP tracks 5 public exploits from researchers including sma11new, BrucessKING, zwlsix. A Nuclei detection template is also available.

AI-analyzed exploit summary The repository contains a functional Python exploit for CVE-2021-36749, an arbitrary file read vulnerability in Apache Druid. The exploit sends a crafted JSON payload to the Druid sampler endpoint to read files from the target system.

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. This issue was previously mentioned as being fixed in 0.21.0 as per CVE-2021-26920 but was not fixed in 0.21.0 or 0.21.1.

Exploits (5)

nomisec WORKING POC 173 stars
by sma11new · infoleak
https://github.com/sma11new/PocList

The repository contains a functional Python exploit for CVE-2021-36749, an arbitrary file read vulnerability in Apache Druid. The exploit sends a crafted JSON payload to the Druid sampler endpoint to read files from the target system.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: Apache Druid <=0.21.1
No auth needed
Prerequisites: Network access to the Druid server · Druid server with vulnerable endpoint exposed
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec WORKING POC 33 stars
by BrucessKING · infoleak
https://github.com/BrucessKING/CVE-2021-36749

The repository contains a functional Python script that exploits CVE-2021-36749, an arbitrary file read vulnerability in Apache Druid. The exploit sends a crafted POST request to the Druid sampler endpoint, leveraging a misconfigured 'file://' URI to read sensitive files like '/etc/passwd'.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: Apache Druid <= 0.21.1
No auth needed
Prerequisites: Network access to the Druid server · Druid server with vulnerable endpoint exposed
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec SUSPICIOUS 1 stars
by zwlsix · poc
https://github.com/zwlsix/apache_druid_CVE-2021-36749

The repository provides instructions for setting up a Docker environment to reproduce CVE-2021-36749 but lacks actual exploit code. It directs users to an external download link for the Docker image, which is a common tactic for suspicious repositories.

Classification
Suspicious 90%
Attack Type
Other
Complexity
Moderate
Reliability
Theoretical
Target: Apache Druid
No auth needed
Prerequisites: Docker environment · External Docker image download
devstral-2 · analyzed Feb 18, 2026 Full analysis →
gitlab WORKING POC
by bybsecs · infoleak
https://gitlab.com/bybsecs/CVE-2021-36749

This repository contains a functional Python exploit for CVE-2021-36749, an arbitrary file read vulnerability in Apache Druid. The script crafts a malicious HTTP request to the Druid sampler endpoint to read files from the target system, such as /etc/passwd, and saves the output to a local file.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: Apache Druid (versions affected by CVE-2021-36749)
No auth needed
Prerequisites: Target URL(s) listed in url.txt · Network access to the Druid server
devstral-2 · analyzed Feb 23, 2026 Full analysis →
nomisec WORKING POC
by Jun-5heng · poc
https://github.com/Jun-5heng/CVE-2021-36749

This repository contains a functional Python script that exploits CVE-2021-36749, an arbitrary file read vulnerability in Apache Druid. The exploit sends a crafted HTTP request to the Druid indexer endpoint to read files from the target system, such as /etc/passwd, and saves the output to a local file.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: Apache Druid (versions affected by CVE-2021-36749)
No auth needed
Prerequisites: Target must be running a vulnerable version of Apache Druid · Network access to the Druid indexer endpoint
devstral-2 · analyzed Feb 18, 2026 Full analysis →

Nuclei Templates (1)

Apache Druid - Local File Inclusion
MEDIUMby _0xf4n9x_

Scores

CVSS v3 6.5
EPSS 0.9384
EPSS Percentile 99.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Details

VulnCheck KEV 2022-03-20
InTheWild.io 2022-05-31
CWE
CWE-863
Status published
Products (2)
apache/druid < 0.22.0
org.apache.druid/druid-core 0 - 0.22.0Maven
Published Sep 24, 2021
Tracked Since Feb 18, 2026