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NVD / CVE Program· CNA mitre

CVE-2021-42227: Cross SIte Scripting (XSS) vulnerability exists in KindEditor 4.1.x via a Google search inurl:/examples/uploadbutton.html and then the .html…

MediumCVSS 6.1 · v3.1—No exploit No fix recorded

Noroxi assessment

Priority: Monitor (action score 24/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.93% (FIRST EPSS); higher than 61.2% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

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

Primary sources: NVD · CVE.org · FIRST EPSS

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).

Published
Oct 14, 2021
Updated
Jun 17, 2026
EPSS
0.9% · 61th percentile

Report tools

JSON

Action score

24

Monitor

Low priority for now.

CVSS
24 / 40 · 6.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.9%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • No fixed version yet

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

Follow CVE-2021-42227

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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Limit the impact of XSSCheck security headers

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Limit the impact of XSSCheck security headers

Is your version affected? Check it

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
kindsoftkindeditor

Limit the impact of XSS

This is a cross-site scripting (XSS) vulnerability. A well-configured Content-Security-Policy doesn't fix it, but greatly reduces its impact. Check your site's CSP and other security headers for free.

Check security headers

Affected versions

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

  • kindsoft kindeditor4.1 and later · up to 4.1.12 inclusive

Package-level exposure

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

EcosystemPackageAffected rangeFix
npmkindeditorup to and including 4.1.12—

Same product

kindsoft: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-42228A Cross Site Request Forgery (CSRF) vulnerability exists in KindEditor 4.1.x, as demonstrated by examples/uploadbutton.html.
    35Monitor
  • CVE-2019-7543In KindEditor 4.1.11, the php/demo.php content1 parameter has a reflected Cross-site Scripting (XSS) vulnerability.
    25Monitor
  • CVE-2020-28717Cross Site Scripting (XSS) vulnerability in content1 parameter in demo.jsp in kindsoft kindeditor version 4.1.12, allows attackers to…
    24Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2021-30086Sep 28, 2021 · Cross Site Scripting (XSS) vulnerability exists in KindEditor (Chinese versions) 4.1.12, which can be exploited by an attacker to obtain…
    24Monitor
  • ← EarlierCVE-2021-37267Sep 28, 2021 · Cross Site Scripting (XSS) vulnerability exists in all versions of KindEditor, which can be exploited by an attacker to obtain user cookie…
    24Monitor

Remediation

Which version to upgrade to

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

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

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.

No dated events beyond publication.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS vector

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

nvd-primary

Root cause

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

The bug in code

The whole CWE-79 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
commentEl.textContent = comment.body;

Attack context

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

ATT&CK techniques

—

All records