rails-ujs vulnerable to DOM Based Cross-site Scripting contenteditable HTML Elements

NOTE: rails-ujs is part of Rails/actionview since 5.1.0.

There is a potential DOM based cross-site scripting issue in rails-ujs which leverages the Clipboard API to target HTML elements that are assigned the contenteditable attribute. This has the potential to occur when pasting malicious HTML content from the clipboard that includes a data-method, data-remote or data-disable-with attribute.

This vulnerability has been assigned the CVE identifier CVE-2023-23913.

Not affected: < 5.1.0 Versions Affected: >= 5.1.0 Fixed Versions: 6.1.7.3, 7.0.4.3

Impact If the specified malicious HTML clipboard content is provided to a contenteditable element, this could result in the arbitrary execution of javascript on the origin in question.

Releases The FIXED releases are available at the normal locations.

Workarounds We recommend that all users upgrade to one of the FIXED versions. In the meantime, users can attempt to mitigate this vulnerability by removing the contenteditable attribute from elements in pages that rails-ujs will interact with.

Patches To aid users who aren’t able to upgrade immediately we have provided patches for the two supported release series. They are in git-am format and consist of a single changeset.

• rails-ujs-data-method-contenteditable-6-1.patch - Patch for 6.1 series
• rails-ujs-data-method-contenteditable-7-0.patch - Patch for 7.0 series

Please note that only the 7.0.Z and 6.1.Z series are supported at present, and 6.0.Z for severe vulnerabilities.

Users of earlier unsupported releases are advised to upgrade as soon as possible as we cannot guarantee the continued availability of security fixes for unsupported releases.

Credits We would like to thank ryotak 15 for reporting this!

• rails-ujs-data-method-contenteditable-6-1.patch (8.5 KB)
• rails-ujs-data-method-contenteditable-7-0.patch (8.5 KB)
• rails-ujs-data-method-contenteditable-main.patch (8.9 KB)