How severe is CVE-2021-33813?

CVE-2021-33813 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-33813?

CVE-2021-33813 affects the following packages: org.jdom:jdom2 (Maven), org.jdom:jdom (Maven). Ecosystems affected: Maven.

How do I fix CVE-2021-33813?

Update org.jdom:jdom2 to 2.0.6.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-33813 is resolved across your whole dependency graph.

How do I detect CVE-2021-33813 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.jdom:jdom2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-33813 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2021-33813 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2021-33813, including 1 in-the-wild exploitation 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-2021-33813?

CVE-2021-33813 has an EPSS (Exploit Prediction Scoring System) score of 19.4%, placing it in the 97th 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. This score warrants monitoring and prompt remediation.

What type of vulnerability is CVE-2021-33813?

CVE-2021-33813 is classified as XML External Entity (XXE) (CWE-611). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-33813 published, and has it been updated?

CVE-2021-33813 was published on June 16, 2021 and was last updated on October 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

HIGH severity

CVE-2021-33813 — jdom2

HIGHFix: hunterhacker/jdom#188

CVE-2021-33813 is a high-severity (CVSS 7.5) XML External Entity (XXE) vulnerability in org.jdom:jdom2. 1 public exploit reference exists, so weaponization risk is real. A fix is available for org.jdom:jdom2 — see the affected versions and patch details below.

XML External Entity (XXE) Injection in JDOM

Also known asBIT-solr-2021-33813GHSA-2363-cqg2-863c

Published

Jun 16, 2021

Updated

Oct 9, 2026

Affected

2 pkgs

Patched

1 / 2

Exploits

1 known

Exploitation data as of Oct 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

19.4%probability of exploitation in next 30 days

Moderate Risk0.00%

Lower risk than most CVEs97th percentile — riskier than 97% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-33813 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

2 pkgs affected

☕org.jdom:jdom2☕org.jdom:jdom

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

An XXE issue in SAXBuilder in JDOM through 2.0.6 allows attackers to cause a denial of service via a crafted HTTP request. As a workaround, to avoid external entities being expanded, one can call builder.setExpandEntities(false) and they won't be expanded.

Affected Packages

2 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.jdom:jdom2`	all versions	2.0.6.1`org.jdom:jdom2:2.0.6.1`
☕Maven	`org.jdom:jdom`	all versions	No fix

Affected Products

6 products · 7 configurations

Application

solrapache

2 versions

8.8.18.9

Application

tikaapache

1 version

1.25

debian linuxdebian

1 version

9.0

fedorafedoraproject

1 version

Application

jdomjdom

≤ 2.0.6

range

communications messaging serveroracle

1 version

8.1

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.

An XXE issue in SAXBuilder in JDOM through 2.0.6 allows attackers to cau…

alephsecurity.comNVDFeb 2023

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.jdom:jdom2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.jdom:jdom2 to 2.0.6.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-33813 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

In OpenShift Container Platform (OCP), the hive and hadoop components that comprise the OCP metering stack, ship the vulnerable version of jdom. Since the release of OCP 4.6, the metering product has been deprecated [1], hence the affected components are marked as wontfix. This may be fixed in the future. This flaw is…

Product	Fixed in	Advisory
Red Hat Fuse 7.11	`jdom`	RHSA-2022:5532
RHDM 7.12.1	`jdom`	RHSA-2022:1110
RHINT Camel-K 1.6.4	`jdom`	RHSA-2022:1029
RHPAM 7.12.1	`jdom`	RHSA-2022:1108

Frequently Asked Questions

An XXE issue in SAXBuilder in JDOM through 2.0.6 allows attackers to cause a denial of service via a crafted HTTP request. As a workaround, to avoid external entities being expanded, one can call `builder.setExpandEntities(false)` and they won't be expanded.

O3 Security · Impact-Aware SCA

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CVE-2021-33813 — jdom2

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Fixing This On Your OS

Frequently Asked Questions

Is CVE-2021-33813 in your dependencies?