CVE-2026-116675: TinyMCE Cross-Site Scripting (XSS) vulnerability using media plugin `data-mce-object` serialization

Severity: high (CVSS 8.5 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-27 · updated 2026-10-28
Weakness: CWE-79

Description

TinyMCE is an open source rich text editor. From 7.9.3 until 7.9.4 and from 8.5.1 until 8.9.3, the media plugin creates elements crafted through data-mce-object in the active document before sanitization. Those elements can execute malicious scripts during processing, resulting in stored cross-site scripting for users with the media plugin enabled. This issue is fixed in versions 8.9.3 and 7.9.4.

Affected products

tinymce: from 8.5.1, < 8.9.3; from 7.9.3, < 7.9.4

References

https://github.com/tinymce/tinymce/commit/bd1ab5ef024c648c3f9c0b409e54a6c227c7d8a2
https://github.com/tinymce/tinymce/releases/tag/8.9.3
https://github.com/tinymce/tinymce/security/advisories/GHSA-mf2p-h6hf-fcwm
https://www.tiny.cloud/docs/tinymce/7/7.9.4-release-notes/#overview
https://www.tiny.cloud/docs/tinymce/latest/8.9.3-release-notes/#overview

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