CVE-2024-43368

The Trix editor, versions prior to 2.1.4, is vulnerable to XSS when pasting malicious code. This vulnerability is a bypass of the fix put in place for https://github.com/basecamp/trix/security/advisories/GHSA-qjqp-xr96-cj99. In https://github.com/basecamp/trix/pull/1149, we added sanitation for Trix attachments with a text/html content type. However, Trix only checks the content type on the paste event's dataTransfer object. As long as the dataTransfer has a content type of text/html, Trix parses its contents and creates an Attachment with them, even if the attachment itself doesn't have a text/html content type. Trix then uses the attachment content to set the attachment element's innerHTML.

Workarounds

This is not really a workaround but something that should be considered in addition to upgrading to the patched version. If affected users can disallow browsers that don't support a Content Security Policy, then this would be an effective workaround for this and all XSS vulnerabilities. Set CSP policies such as script-src 'self' to ensure that only scripts hosted on the same origin are executed, and explicitly prohibit inline scripts using script-src-elem.

References

• https://github.com/basecamp/trix/pull/1156
• https://github.com/basecamp/trix/releases/tag/v2.1.4
• https://github.com/basecamp/trix/pull/1149
• https://github.com/basecamp/trix/security/advisories/GHSA-qjqp-xr96-cj99
• MDN docs for DataTransfer

Credits

This vulnerability was reported by HackerOne researcher thwin_htet.

An attacker could trick a user to copy and paste malicious code that would execute arbitrary JavaScript code within the context of the user's session, potentially leading to unauthorized actions being performed or sensitive information being disclosed.

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-2024-43368 has a CVSS score of 6.5 (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 (2.1.4); upgrading removes the vulnerable code path.

Kodem intelligence

Update Recommendation: Users should upgrade to Trix editor version 2.1.4 or later, which incorporates proper sanitization of input from copied content.

1. What is CVE-2024-43368? CVE-2024-43368 is a medium-severity cross-site scripting (XSS) vulnerability in trix (npm), affecting versions < 2.1.4. It is fixed in 2.1.4. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2024-43368? CVE-2024-43368 has a CVSS score of 6.5 (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 versions of trix are affected by CVE-2024-43368? trix (npm) versions < 2.1.4 is affected.
4. Is there a fix for CVE-2024-43368? Yes. CVE-2024-43368 is fixed in 2.1.4. Upgrade to this version or later.
5. Is CVE-2024-43368 exploitable, and should I be worried? Whether CVE-2024-43368 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-2024-43368 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-2024-43368? Upgrade trix to 2.1.4 or later.