TinyMCE Cross-Site Scripting (XSS) vulnerability through `mce:protected` comments

### Impact Stored XSS vulnerability via forged mce:protected comments. Allows attackers to bypass sanitization and inject scripts that execute when content is restored. Impacts users who utilize the protect option. ### Patches Patched by validating decoded mce:protected content against configured protect regex rules before restoring. Users should upgrade to the latest patched version. ### Workarounds No official workaround available. ### Fix To avoid this vulnerability: Upgrade to TinyMCE 8.5.1 or higher. Upgrade to TinyMCE 7.9.3 or higher. Upgrade to TinyMCE 5.11.1 LTS or higher for TinyMCE 5.x (only available as part of commercial [long-term support](https://www.tiny.cloud/long-term-support/) contract). ### Acknowledgements Tiny thanks [Ivan Babenko](https://github.com/he1d3n) for their help identifying this vulnerability.

Source published

5 Jun 2026 20:29:07 UTC

Source modified

15 Jul 2026 21:15:18 UTC

Observed here

23 Oct 2026 16:01:25 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

Publisher rating · HIGH