CKEditor 4.0 vulnerability in the HTML Data ProcessorGHSA-vcjf-mgcg-jxjq
MEDIUMGHSA-vcjf-mgcg-jxjq 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.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-vcjf-mgcg-jxjq 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
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.
ckeditor4npmDescription
A cross-site scripting (XSS) vulnerability in the HTML Data Processor for CKEditor 4.0 before 4.14.0 allows remote attackers to inject arbitrary web script through a crafted "protected" comment (with the cke_protected syntax).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | ckeditor4 | all versions | 4.14.0npm install ckeditor4@4.14.0 |
Affected Products
ckeditorckeditordrupaldrupalfedorafedoraprojectagile product lifecycle managementoracleapplication expressoraclebanking enterprise default managementoracleDetection & mitigation playbook
Open-source dependencyDetect
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.
Fix
Update ckeditor4 to 4.14.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-vcjf-mgcg-jxjq is resolved across your whole dependency graph.
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.
Frequently Asked Questions
Is GHSA-vcjf-mgcg-jxjq in your dependencies?
Find it across npm, including transitive dependencies.