How severe is CVE-2021-42227?

CVE-2021-42227 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-42227?

CVE-2021-42227 affects the following packages: kindeditor (npm). Ecosystems affected: npm.

How do I fix CVE-2021-42227?

No patched version of kindeditor has shipped for CVE-2021-42227 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

How do I detect CVE-2021-42227 in my npm dependencies?

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

How do I mitigate CVE-2021-42227 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2021-42227 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2021-42227, 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-2021-42227?

CVE-2021-42227 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 59th 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 indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-42227?

CVE-2021-42227 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2021-42227 published, and has it been updated?

CVE-2021-42227 was published on October 14, 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.

📦

📦 npm

Not in CISA KEV

MEDIUM severity

CVE-2021-42227 — kindeditor

MEDIUM

CVE-2021-42227 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in kindeditor. 1 public exploit reference exists, so weaponization risk is real. No vendor fix is recorded yet; mitigation options are listed below.

Cross site scripting in kindeditor

Also known asGHSA-wv83-jrfh-rp33

Published

Oct 14, 2021

Updated

Jul 9, 2026

Affected

1 pkg

Patched

See advisory

Exploits

1 known

Exploitation data as of Oct 5, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk+0.03%

Lower risk than most CVEs59th percentile — riskier than 59% of all scored CVEsHighest risk

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

How urgent is this, really

CVE-2021-42227 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

15other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

kindeditornpm

184downloads / week

Description

Cross SIte Scripting (XSS) vulnerability exists in KindEditor 4.1.x via a Google search inurl:/examples/uploadbutton.html and then the .html file on the website that uses this editor (the file suffix is allowed).

Affected Packages

1 total

Ecosystem	Package	Vulnerable range	Fix
📦npm	`kindeditor`	all versions	No fix

Affected Products

1 product · 1 configurations

Application

kindeditorkindsoft

≥ 4.1 && ≤ 4.1.12

range

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.

Cross SIte Scripting (XSS) vulnerability exists in KindEditor 4.1.x via …

github.comNVDOct 2021

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for kindeditor, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of kindeditor has shipped for CVE-2021-42227 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-42227 in your dependencies?

Find it across npm, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

6.1/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

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

CWE Classification

CWE-79Cross-site Scripting (XSS)

Weaponization

No known public exploit tooling found.

OpenSSF Scorecard

Package health score

kindeditor

1.9/10

Code-Review2/10

Maintained0/10

Branch-Protection0/10

Assessed Sep 28, 2026

Timeline

Disclosed

Oct 14, 2021

First exploit

Oct 19, 2021

5 days after disclosure — rapid exploitation

Last updated

Jul 9, 2026

Identifiers

CVE-2021-42227

GHSA-wv83-jrfh-rp33

References

Advisorynvd.nist.gov Packagegithub.com Evidencegithub.com

Related vulnerabilities

Also affects kindeditor

This CVE is medium severity; 1 of 1 other CVE affecting kindeditor is rated as high or higher (top: high).

CVE-2021-42228

Same weakness: CWE-79

This CVE is medium severity; 7 of 7 other CVEs with CWE-79 are rated as high or higher (top: high).

CVE-2026-91127CVE-2026-77606CVE-2026-84992CVE-2026-77608CVE-2026-77607GHSA-9rcc-pmj8-ffhrCVE-2026-77616Browse all CWE-79

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedJul 9, 2026