CVE-2023-45819

TinyMCE is an open source rich text editor. 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. 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. Users are advised to upgrade. There are no known workarounds for this vulnerability.

TinyMCE is an open source rich text editor. 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. 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. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Impact

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.

Patches

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.

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

Impact

A cross-site scripting (XSS) vulnerability was discovered in the URL sanitization logic of the core parser for form elements. The vulnerability allowed arbitrary JavaScript execution when inserting a specially crafted piece of content into the editor using the clipboard or APIs, and then submitting the form. However, as TinyMCE does not allow forms to be submitted while editing, the vulnerability could only be triggered when the content was previewed or rendered outside of the editor. This impacts all users who are using TinyMCE 5.7.0 or lower.

Patches

This vulnerability has been patched in TinyMCE 5.7.1 by improved URL sanitization logic.

Workarounds

To work around this vulnerability, either:

• Upgrade to TinyMCE 5.7.1 or higher
• Manually sanitize form URL attributes using a TinyMCE node filter.
• Disable form elements in your content using the invalid_elements setting.

Example: Sanitizing using a node filter

editor.parser.addNodeFilter('form', function(nodes) {
  nodes.forEach(function(node) {
    if (node.attributes) {
      node.attributes.forEach(function(attr) {
        var name = attr.name;
        var value = attr.value;
        // Sanitize the attribute value here or remove it entirely
        var sanitizedValue = ...;
        node.attr(name, santizedValue);
      });
    }
  });
});

Example: Using invalid_elements

invalid_elements: 'form'

Acknowledgements

Tiny Technologies would like to thank Mikhail Khramenkov at Solar Security Research Team for discovering this vulnerability.

References

https://www.tiny.cloud/docs/release-notes/release-notes571/#securityfixes

For more information

If you have any questions or comments about this advisory:

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

TinyMCE is an open source rich text editor. 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. 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. Users are advised to upgrade. There are no known workarounds for this vulnerability.

TinyMCE is an open source rich text editor. 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. 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. Users are advised to upgrade. There are no known workarounds for this vulnerability.