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CVE-2021-36749· NVD / CVE Program· CNA apache

Apache Druid: The HTTP inputSource allows authenticated users to read data from other sources than intended (incomplete fix of CVE-2021-26920)

Noroxi assessment

Priority: Plan (action score 50/100)

  • A ready-made attack module is public (Nuclei); exploiting it takes no special expertise.
  • Probability of exploitation in the next 30 days: 80.9% (FIRST EPSS); higher than 99.6% of all records.
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Apache Software Foundation Apache Druid 0.21.0.

Add it to your regular patch cycle. Upgrade to Apache Software Foundation Apache Druid 0.21.0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

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.

MediumCVSS 6.5 · v3.1—Proof of concept Fix available
Published
Sep 24, 2021
Updated
Jun 16, 2026
EPSS
80.9% · 100th percentile

Report tools

JSON

Action score

50

Plan

Add it to your regular patch cycle.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
24 / 30 · 80.9%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
apachedruid

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • apache druidbefore 0.22.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (apache). Independent of NVD's CPE analysis and usually ahead of it.

  • Apache Software Foundation Apache Druid

    • 0.21.1 and earlier and later · up to and including 0.21.1affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Mavenorg.apache.druid:druid-corebefore 0.22.00.22.0

Same product

apache: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-25646Authenticated users can override system configurations in their requests which allows them to execute arbitrary code.
    65This week
  • CVE-2021-26919Apache Druid Authenticated users can execute arbitrary code from malicious MySQL database systems.
    46Plan
  • CVE-2026-23906Apache Druid: Authentication Bypass via LDAP Anonymous Bind
    39Monitor
  • CVE-2025-59390Apache Druid: Kerberos authenticaton chooses a cryptographically unsecure secret if not configured explicitly.
    39Monitor
  • CVE-2021-26920Apache Druid: The HTTP inputSource allows authenticated users to read data from other sources than intended
    29Monitor
  • CVE-2020-1958When LDAP authentication is enabled in Apache Druid 0.17.0, callers of Druid APIs with a valid set of LDAP credentials can bypass the creden
    27Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Apache Software Foundation Apache Druid0.21.0 · descriptionVendor (CNA)
Maven:org.apache.druid:druid-core0.22.0Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Nuclei detection template ×1
  • Proof-of-concept repository on GitHub ×4

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Nuclei detection templateNuclei template CVE-2021-36749 —
Proof-of-concept repository on GitHubstars:1782021-05-22
Proof-of-concept repository on GitHubstars:332021-10-14
Proof-of-concept repository on GitHubstars:12021-11-21
Proof-of-concept repository on GitHubstars:02021-12-12

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. First PoC-125 d
  2. Published
  3. TodayOct 13, 2026+1845 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-863 · Incorrect Authorization

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records