CVE-2025-25299: CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture. During a recent internal audit, a Cross-Site Scripting (XSS) vulnerabilit...

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.

Metrics

CVSS 4.0

2.3/10

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.56%

42.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

References

Timeline

Published: Feb 20, 2025
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2025-25299?

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.

How severe is CVE-2025-25299?

CVE-2025-25299 has a CVSS score of 2.3/10 (LOW severity). The EPSS model estimates a 0.56% probability of exploitation in the next 30 days.

How do I fix CVE-2025-25299?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.