How severe is CVE-2021-36749?

CVE-2021-36749 has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-36749?

CVE-2021-36749 affects the following packages: org.apache.druid:druid-core (Maven). Ecosystems affected: Maven.

How do I fix CVE-2021-36749?

Update org.apache.druid:druid-core to 0.22.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-36749 is resolved across your whole dependency graph.

How do I detect CVE-2021-36749 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.druid:druid-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-36749 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2021-36749?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2021-36749 can be triaged on real exposure rather than presence alone.

Is CVE-2021-36749 actively exploited in the wild?

Yes. There are 7 known exploit references for CVE-2021-36749, including 5 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-36749?

CVE-2021-36749 has an EPSS (Exploit Prediction Scoring System) score of 80.9%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2021-36749?

CVE-2021-36749 is classified as CWE-863 (CWE-863). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Is there exploit tooling available for CVE-2021-36749?

A Nuclei detection template exists for CVE-2021-36749, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2021-36749 published, and has it been updated?

CVE-2021-36749 was published on September 24, 2021 and was last updated on July 9, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

MEDIUM severity

CVE-2021-36749 — druid-core

MEDIUM

CVE-2021-36749 is a medium-severity (CVSS 6.5) CWE-863 vulnerability in org.apache.druid:druid-core. 7 public exploit references exist, so weaponization risk is real. A fix is available for org.apache.druid:druid-core — see the affected versions and patch details below.

Druid ingestion system Authenticated users can read data from other sources than intended

Also known asGHSA-9p5g-vg43-mj5r

Published

Sep 24, 2021

Updated

Jul 9, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

7 known

Exploitation data as of Sep 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

80.9%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

CVE-2021-36749 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 377,636 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

1 pkg affected

☕org.apache.druid:druid-core

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.druid:druid-core`	all versions	0.22.0`org.apache.druid:druid-core:0.22.0`

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.