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MEDIUM severity

CVE-2020-9281 — ckeditor4

MEDIUM

CVE-2020-9281 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in ckeditor4. A fix is available for ckeditor4 — see the affected versions and patch details below.

CKEditor 4.0 vulnerability in the HTML Data Processor

Also known asBIT-drupal-2020-9281GHSA-vcjf-mgcg-jxjq
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
4.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs91th percentile — riskier than 91% of all scored CVEsHighest risk
0.25%1.93%3.60%5.27%1.2%4.3%Apr 26Aug 26Oct 26

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

How urgent is this, really

CVE-2020-9281 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% 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.

27other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
ckeditor4npm
66Kdownloads / week

Description

A cross-site scripting (XSS) vulnerability in the HTML Data Processor for CKEditor 4.0 before 4.14 allows remote attackers to inject arbitrary web script through a crafted "protected" comment (with the cke_protected syntax).

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmckeditor4all versions4.14.0npm install ckeditor4@4.14.0

Affected Products

11 products · 24 configurations
Application
ckeditorckeditor
≥ 4.0 && < 4.14
range
Application
drupaldrupal
≥ 8.8.0 && < 8.8.4
range
OS
fedorafedoraproject
3 versions
303132
Application
agile product lifecycle managementoracle
2 versions
9.3.59.3.6
Application
application expressoracle
< 20.2
range
Application
banking enterprise default managementoracle
5 versions
2.6.22.7.02.7.12.10.02.12.0

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ckeditor4, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update ckeditor4 to 4.14.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-9281 is resolved across your whole dependency graph.

  3. Workarounds

    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.

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.

UbuntuMEDIUM
USN-5340-1UbuntuUSN-5340-2Ubuntu

Frequently Asked Questions

A cross-site scripting (XSS) vulnerability in the HTML Data Processor for CKEditor 4.0 before 4.14 allows remote attackers to inject arbitrary web script through a crafted "protected" comment (with the cke_protected syntax).
O3 Security · Impact-Aware SCA

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CVE-2020-9281: ckeditor4 XSS — Fixed in 4.14.0