CVE-2024-38356

TinyMCE is an open source rich text editor. A cross-site scripting (XSS) vulnerability was discovered in TinyMCE’s content extraction code. When using the noneditable_regexp option, specially crafted HTML attributes containing malicious code were able to be executed when content was extracted from the editor. This vulnerability has been patched in TinyMCE 7.2.0, TinyMCE 6.8.4 and TinyMCE 5.11.0 LTS by ensuring that, when using the noneditable_regexp option, any content within an attribute is properly verified to match the configured regular expression before being added. 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 content extraction code. When using the noneditable_regexp option, specially crafted HTML attributes containing malicious code were able to be executed when content was extracted from the editor. This vulnerability has been patched in TinyMCE 7.2.0, TinyMCE 6.8.4 and TinyMCE 5.11.0 LTS by ensuring that, when using the noneditable_regexp option, any content within an attribute is properly verified to match the configured regular expression before being added. 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 content extraction code. When using the noneditable_regexp option, specially crafted HTML attributes containing malicious code were able to be executed when content was extracted from the editor.

Patches

This vulnerability has been patched in TinyMCE 7.2.0, TinyMCE 6.8.4 and TinyMCE 5.11.0 LTS by ensuring that, when using the noneditable_regexp option, any content within an attribute is properly verified to match the configured regular expression before being added.

Fix

To avoid this vulnerability:

• Upgrade to TinyMCE 7.2.0 or higher.
• Upgrade to TinyMCE 6.8.4 or higher for TinyMCE 6.x.
• Upgrade to TinyMCE 5.11.0 LTS or higher for TinyMCE 5.x (only available as part of commercial long-term support contract).

References

• TinyMCE 6.8.4
• TinyMCE 7.2.0

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 content extraction code. When using the noneditable_regexp option, specially crafted HTML attributes containing malicious code were able to be executed when content was extracted from the editor. This vulnerability has been patched in TinyMCE 7.2.0, TinyMCE 6.8.4 and TinyMCE 5.11.0 LTS by ensuring that, when using the noneditable_regexp option, any content within an attribute is properly verified to match the configured regular expression before being added. 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 content extraction code. When using the noneditable_regexp option, specially crafted HTML attributes containing malicious code were able to be executed when content was extracted from the editor. This vulnerability has been patched in TinyMCE 7.2.0, TinyMCE 6.8.4 and TinyMCE 5.11.0 LTS by ensuring that, when using the noneditable_regexp option, any content within an attribute is properly verified to match the configured regular expression before being added. Users are advised to upgrade. There are no known workarounds for this vulnerability.