Executive brief
TinyMCE, a widely used rich text editor for web applications, is vulnerable to a security flaw that allows attackers to inject malicious scripts into saved content. If a user views or edits this compromised content, the script can execute in their browser, potentially leading to unauthorized data access or account takeover. This issue specifically affects organizations using the editor's content protection features.
Technical details
A stored cross-site scripting (XSS) vulnerability exists in TinyMCE due to improper neutralization of 'mce:protected' comments. Attackers can bypass the editor's sanitization filters by forging these comments, which are intended to protect specific code blocks from being altered. When the editor restores the content for display or editing, the malicious payload is executed in the context of the user's session. The vulnerability requires low privileges to submit content and some user interaction to view the affected page. The fix involves validating decoded protected content against configured regex rules before restoration.
Affected products
- Tiny TinyMCE < 5.11.1, >= 6.0.0, < 7.9.3, >= 8.0.0, < 8.5.1
Timeline
- 2026-05-20: disclosed
- 2026-05-28: advisory: NVD publication date
- 2026-06-05: advisory: GitHub Advisory published