TinyMCE Cross-Site Scripting (XSS) Vulnerability in Handling iframes
Summary
CVE-2024-29203: TinyMCE Cross-Site Scripting (XSS) vulnerability in handling iframes. Affects tinymce versions < 6.8.1. Fixed in 6.8.1. How to fix ↓
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Background
TinyMCE is a popular open-source WYSIWYG editor used for embedding rich text content into web applications. It provides a user-friendly interface for creating and editing HTML content. However, a cross-site scripting (XSS) vulnerability has been discovered in TinyMCE's content insertion code. This vulnerability allows malicious code within iframe elements to execute when inserted into the editor. While these iframes are restricted by same-origin browser protections, they can still trigger operations such as downloading malicious assets.
Vulnerability Detail
The XSS vulnerability in TinyMCE's content insertion code allows for the execution of malicious code within iframe elements. This can lead to various security risks, including unauthorized access, data theft, and the potential for further exploitation. The vulnerability arises from a lack of proper sanitization and validation of the inserted content. Attackers can exploit this vulnerability by crafting malicious iframes and tricking users into inserting them into the editor.
How To Fix
Latest published version: 8.10.0 as of 23 Oct 2026
npm install tinymce@8.10.0Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
6.8.1
This is the first release that contains the fix.
npm install tinymce@6.8.1Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a workaround, you can configure the HTTP Content-Security-Policy (CSP) frame-src or object-src to restrict or block the loading of unauthorized URLs. This can help mitigate the risk of XSS attacks through iframes. Refer to the TinyMCE Content Security Policy Guide for detailed instructions on implementing CSP.
Conclusion
The TinyMCE Cross-Site Scripting (XSS) vulnerability in handling iframes can pose significant security risks to web applications using this editor. It is crucial to update to the latest version of TinyMCE and enable the necessary options to mitigate the vulnerability. Additionally, configuring the Content-Security-Policy can provide an extra layer of protection. For further support on vulnerability remediation, you can contact DevNack.com.
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FAQ
The vulnerability allows for the execution of malicious code within iframes, which can lead to unauthorized access, data theft, and further exploitation.
Update to TinyMCE version 6.8.1 or later and enable the sandbox_iframes option. Additionally, configure the Content-Security-Policy to restrict unauthorized URLs.
Yes, you can configure the Content-Security-Policy to restrict or block the loading of unauthorized URLs.
Yes, this vulnerability can be exploited remotely by tricking users into inserting malicious iframes into the TinyMCE editor.
There is no information available regarding active exploitation of this vulnerability at the moment.
References
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