Description

CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture. During a recent internal audit, a Cross-Site Scripting (XSS) vulnerability was discovered in the CKEditor 5 real-time collaboration package. This vulnerability affects user markers, which represent users' positions within the document. It can lead to unauthorized JavaScript code execution, which might happen with a very specific editor and token endpoint configuration. This vulnerability affects only installations with Real-time collaborative editing enabled. The problem has been recognized and patched. The fix is available in version 44.2.1 (and above). Users are advised to upgrade. There are no known workarounds for this vulnerability.

Classification

CVE ID: CVE-2025-25299

CVSS Base Severity: LOW

CVSS Base Score: 2.3

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

Affected Products

Vendor: ckeditor

Product: ckeditor5

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.09% (probability of being exploited)

EPSS Percentile: 23.33% (scored less or equal to compared to others)

EPSS Date: 2025-03-21 (when was this score calculated)

References

https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-j3mm-wmfm-mwvh
https://ckeditor.com/docs/ckeditor5/latest/features/collaboration/real-time-collaboration/real-time-collaboration.html
https://github.com/ckeditor/ckeditor5/releases/tag/v44.2.1

Timeline