XSS in Ckeditor Ckeditor5
CVE-2026-116688
CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture. From 45.0.0 until 47.7.4 and 48.5.1, the engine uses a vulnerable es-toolkit version whose prototype-pollution behavior can be reached while CKEditor processes incoming style attribute values. Crafted editor content can thereby cause unauthorized JavaScript execution in the browser. This issue is fixed in versions 47.7.4 and 48.5.1.
Vulnerability class: XSS (Cross-Site Scripting)
Published .
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Ckeditor Ckeditor5 — versions >= 45.0.0, < 47.7.4, >= 48.0.0, < 48.5.1
Weakness classification (CWE)
References
- github.com/ckeditor/ckeditor5/security/advisories/GHSA-rh54-vffm-5fvp
- github.com/ckeditor/ckeditor5/commit/4d9c5bb34f63cd956d15ccafbe584e14280c86a0
- github.com/ckeditor/ckeditor5/commit/a750e38635db6a18c5b11599c09f4fd702850423
- github.com/ckeditor/ckeditor5/releases/tag/v47.7.4
- github.com/ckeditor/ckeditor5/releases/tag/v48.5.1
Frequently asked questions
- What is CVE-2026-116688?
- CVE-2026-116688 is a high-severity vulnerability in Ckeditor Ckeditor5, classified under Cross-site Scripting. CVSS score: 8.1/10. Published 2026-10-27.
- How severe is CVE-2026-116688?
- High severity. CVSS v3 base score is 8.1 out of 10.