CVE-2026-47760: TinyMCE XSS via improper SVG namespace handling in sanitizer

Executive brief

TinyMCE is a widely used rich-text editor integrated into many web applications to allow users to create and format content. A security flaw in its content filtering system allows an attacker to bypass safety checks by using specially formatted images (SVGs). If exploited, this could allow an attacker to run malicious scripts in another user's browser, potentially leading to unauthorized access to user data or account takeover.

Technical details

A Cross-Site Scripting (XSS) vulnerability exists in TinyMCE versions 6.8.0 through 7.0.x. The root cause is improper SVG namespace scope handling within the editor's HTML sanitizer. By crafting a payload using nested <svg> elements, an attacker can bypass attribute sanitization to execute arbitrary JavaScript. Exploitation requires network access and low privileges to submit content, plus interaction from another user to view the malicious content. The issue is resolved in TinyMCE version 7.1.0 through a rewrite of the affected sanitization logic.

Affected products

• Tiny TinyMCE >= 6.8.0, < 7.1.0

Timeline

• 2026-05-20: disclosed: Initial disclosure to vendor
• 2026-05-28: advisory: NVD publication date
• 2026-06-05: advisory: GitHub Advisory Database publication date

References

• https://api.github.com/users/maple3142
• https://github.com/maple3142
• https://api.github.com/users/maple3142/gists%7B/gist_id%7D
• https://api.github.com/users/maple3142/repos
• https://avatars.githubusercontent.com/u/9370547?v=4
• https://api.github.com/users/maple3142/events%7B/privacy%7D