What is CVE-2025-25299?

CVE-2025-25299 is a medium-severity cross-site scripting (XSS) vulnerability in @ckeditor/ckeditor5-real-time-collaboration (npm), affecting versions >= 41.3.0, <= 44.2.0. It is fixed in 44.2.1. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.

Which packages are affected by CVE-2025-25299?

@ckeditor/ckeditor5-real-time-collaboration (npm) versions >= 41.3.0, = 42.0.0, < 44.2.0.

Is there a fix for CVE-2025-25299?

Yes. CVE-2025-25299 is fixed in 44.2.1. Upgrade to this version or later.

Is CVE-2025-25299 exploitable, and should I be worried?

Whether CVE-2025-25299 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether CVE-2025-25299 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

How do I fix CVE-2025-25299?

Upgrade: @ckeditor/ckeditor5-real-time-collaboration to 44.2.1 or later, ckeditor5-premium-features to 44.2.1 or later.

CVE-2025-25299

Q: Which packages are affected by CVE-2025-25299?

@ckeditor/ckeditor5-real-time-collaboration (npm) versions >= 41.3.0, = 42.0.0, < 44.2.0.

Q: Is there a fix for CVE-2025-25299?

Yes. CVE-2025-25299 is fixed in 44.2.1. Upgrade to this version or later.

Q: Is CVE-2025-25299 exploitable, and should I be worried?

Whether CVE-2025-25299 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether CVE-2025-25299 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix CVE-2025-25299?

Upgrade: @ckeditor/ckeditor5-real-time-collaboration to 44.2.1 or later, ckeditor5-premium-features to 44.2.1 or later.

Summary

Cross-site scripting (XSS) in the CKEditor 5 real-time collaboration package

For more information

Email us at [email protected] if you have any questions or comments about this advisory.

Impact

During a recent internal audit, we identified a Cross-Site Scripting (XSS) vulnerability in the CKEditor 5 real-time collaboration package. This vulnerability can lead to unauthorized JavaScript code execution and affects user markers, which represent users' positions within the document.

This vulnerability affects only installations with Real-time collaborative editing enabled.

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

Affected versions

@ckeditor/ckeditor5-real-time-collaboration (>= 41.3.0, <= 44.2.0) ckeditor5-premium-features (>= 42.0.0, < 44.2.0)

Security releases

@ckeditor/ckeditor5-real-time-collaboration → 44.2.1 (npm) ckeditor5-premium-features → 44.2.1 (npm)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

The problem has been recognized and patched. The fix will be available in version 44.2.1 (and above).

Frequently Asked Questions

What is CVE-2025-25299? CVE-2025-25299 is a medium-severity cross-site scripting (XSS) vulnerability in @ckeditor/ckeditor5-real-time-collaboration (npm), affecting versions >= 41.3.0, <= 44.2.0. It is fixed in 44.2.1. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
Which packages are affected by CVE-2025-25299?
- @ckeditor/ckeditor5-real-time-collaboration (npm) (versions >= 41.3.0, <= 44.2.0)
- ckeditor5-premium-features (npm) (versions >= 42.0.0, < 44.2.0)
Is there a fix for CVE-2025-25299? Yes. CVE-2025-25299 is fixed in 44.2.1. Upgrade to this version or later.
Is CVE-2025-25299 exploitable, and should I be worried? Whether CVE-2025-25299 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether CVE-2025-25299 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix CVE-2025-25299?
- Upgrade @ckeditor/ckeditor5-real-time-collaboration to 44.2.1 or later
- Upgrade ckeditor5-premium-features to 44.2.1 or later