CVE-2023-45819

TinyMCE XSS vulnerability in notificationManager.open API

Fix

To avoid this vulnerability:

• Upgrade to TinyMCE 5.10.8 or higher for TinyMCE 5.x.
• Upgrade to TinyMCE 6.7.1 or higher for TinyMCE 6.x.

References

• https://tiny.cloud/docs/release-notes/release-notes5108/#securityfixes
• https://tiny.cloud/docs/tinymce/6/6.7.1-release-notes/#security-fixes

For more information

If you have any questions or comments about this advisory:

• Email us at [email protected]
• Open an issue in the TinyMCE repo

A cross-site scripting (XSS) vulnerability was discovered in TinyMCE’s Notification Manager API. The vulnerability exploits TinyMCE's unfiltered notification system, which is used in error handling. The conditions for this exploit requires carefully crafted malicious content to have been inserted into the editor and a notification to have been triggered.

When a notification was opened, the HTML within the text argument was displayed unfiltered in the notification. The vulnerability allowed arbitrary JavaScript execution when an notification presented in the TinyMCE UI for the current user. This issue could also be exploited by any integration which uses a TinyMCE notification to display unfiltered HTML content.

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.

CVE-2023-45819 has a CVSS score of 6.1 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (6.7.1, 5.10.8); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

This vulnerability has been patched in TinyMCE 5.10.8 and TinyMCE 6.7.1 by ensuring that the HTML displayed in the notification is sanitized, preventing the exploit.

1. What is CVE-2023-45819? CVE-2023-45819 is a medium-severity cross-site scripting (XSS) vulnerability in tinymce (npm), affecting versions >= 6.0.0, < 6.7.1. It is fixed in 6.7.1, 5.10.8. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2023-45819? CVE-2023-45819 has a CVSS score of 6.1 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2023-45819?
   • tinymce (npm) (versions >= 6.0.0, < 6.7.1)
   • TinyMCE (nuget) (versions >= 6.0.0, < 6.7.1)
   • tinymce/tinymce (composer) (versions >= 6.0.0, < 6.7.1)
4. Is there a fix for CVE-2023-45819? Yes. CVE-2023-45819 is fixed in 6.7.1, 5.10.8. Upgrade to this version or later.
5. Is CVE-2023-45819 exploitable, and should I be worried? Whether CVE-2023-45819 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
6. What actually determines whether CVE-2023-45819 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.
7. How do I fix CVE-2023-45819?
   • Upgrade tinymce to 6.7.1 or later
   • Upgrade TinyMCE to 6.7.1 or later
   • Upgrade tinymce/tinymce to 6.7.1 or later
   • Upgrade tinymce to 5.10.8 or later
   • Upgrade TinyMCE to 5.10.8 or later
   • Upgrade tinymce/tinymce to 5.10.8 or later

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