TinyMCE Cross-Site Scripting (XSS) vulnerability using through data-mce- prefixed src, href, style attributes
Published 5 Jun 2026 · Updated 10 Sept 2026
Affected packages
- Affected
- <=5.10.9
- Fixed in
- No fix released
- Affected
- >=6.0.0 <7.9.3
- Fixed in
- 7.9.3
npm install tinymce@7.9.3- Affected
- >=8.0.0 <8.5.1
- Fixed in
- 8.5.1
npm install tinymce@8.5.1- Affected
- <=5.10.9
- Fixed in
- No fix released
- Affected
- >=6.0.0 <7.9.3
- Fixed in
- 7.9.3
composer require tinymce/tinymce:^7.9.3- Affected
- >=8.0.0 <8.5.1
- Fixed in
- 8.5.1
composer require tinymce/tinymce:^8.5.1Details
Impact
Stored XSS vulnerability via unsanitized data-mce-* attributes (data-mce-href, data-mce-src, data-mce-style). Allows attackers to inject malicious values that override safe attributes during serialization, bypassing validation.
Patches
Patched by stripping unsafe data-mce-* attributes during parsing. Users should upgrade to the latest patched versions (5 LTS, 7.x, 8.x).
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 contract).
Acknowledgements
Tiny thanks Tadi Kadango (website) and Ivan Babenko for their help identifying this vulnerability.
Is GHSA-q742-qvgc-gc2f in any of your client repos?
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References
Advisory data from OSV.dev (opens OSV.dev in a new tab), refreshed daily.