XSS in Ckeditor Ckeditor5
CVE-2026-28343
CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture. Starting in version 29.0.0 and prior to version 47.6.0, a cross-site scripting (XSS) vulnerability has been discovered in the General HTML Support feature. This vulnerability could be triggered by inserting specially crafted markup, leading to unauthorized JavaScript code execution, if the editor instance used an unsafe General HTML Support configuration. This issue has been patched in version 47.6.0.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.003 (18.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N.
Affected products
- Ckeditor Ckeditor5 — versions >= 29.0.0, < 47.6.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-28343?
- CVE-2026-28343 is a medium-severity vulnerability in Ckeditor Ckeditor5, classified under Cross-site Scripting. CVSS score: 6.4/10. Published 2026-03-05.
- How severe is CVE-2026-28343?
- Medium severity. CVSS v3 base score is 6.4 out of 10.