CVE-2024-29881

TinyMCE Cross-Site Scripting (XSS) vulnerability in handling external SVG files through Object or Embed elements

Workarounds

If you are using TinyMCE 6.8.1 or higher, set convert_unsafe_embeds to true. For any earlier versions, a custom NodeFilter is recommended to remove or modify any object or embed elements. This can be added using the editor.parser.addNodeFilter and editor.serializer.addNodeFilter APIs.

Acknowledgements

Tiny Technologies would like to thank Toni Huttunen of Fraktal Oy for discovering this vulnerability.

References

• TinyMCE 6.8.1
• TinyMCE 7.0.0

A cross-site scripting (XSS) vulnerability was discovered in TinyMCE’s content loading and content inserting code. A SVG image could be loaded though an object or embed element and that image could potentially contain a XSS payload.

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-2024-29881 has a CVSS score of 4.3 (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 (7.0.0); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

TinyMCE 6.8.1 introduced a new convert_unsafe_embeds option to automatically convert object and embed elements respective of their type attribute. From TinyMCE 7.0.0 onwards, the convert_unsafe_embeds option is enabled by default.

1. What is CVE-2024-29881? CVE-2024-29881 is a medium-severity cross-site scripting (XSS) vulnerability in tinymce/tinymce (composer), affecting versions < 7.0.0. It is fixed in 7.0.0. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2024-29881? CVE-2024-29881 has a CVSS score of 4.3 (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 packages are affected by CVE-2024-29881?
   • tinymce/tinymce (composer) (versions < 7.0.0)
   • tinymce (npm) (versions < 7.0.0)
   • TinyMCE (nuget) (versions < 7.0.0)
4. Is there a fix for CVE-2024-29881? Yes. CVE-2024-29881 is fixed in 7.0.0. Upgrade to this version or later.
5. Is CVE-2024-29881 exploitable, and should I be worried? Whether CVE-2024-29881 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-2024-29881 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-2024-29881?
   • Upgrade tinymce/tinymce to 7.0.0 or later
   • Upgrade tinymce to 7.0.0 or later
   • Upgrade TinyMCE to 7.0.0 or later

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