TinyMCE mXSS vulnerability in undo/redo, getContent API, resetContent API, and Autosave plugin
Impact
A mutation cross-site scripting (mXSS) vulnerability was discovered in TinyMCE’s core undo and redo functionality. When a carefully-crafted HTML snippet passes the XSS sanitisation layer, it is manipulated as a string by internal trimming functions before being stored in the undo stack. If the HTML snippet is restored from the undo stack, the combination of the string manipulation and reparative parsing by either the browser's native DOMParser API (TinyMCE 6) or the SaxParser API (TinyMCE 5) mutates the HTML maliciously, allowing an XSS payload to be executed. This vulnerability also impacts these related TinyMCE APIs and plugins:
Patches
This vulnerability has been patched in TinyMCE 5.10.8 and TinyMCE 6.7.1 by ensuring HTML is trimmed using node-level manipulation instead of string manipulation.
Fix
To avoid this vulnerability:
- Upgrade to TinyMCE 5.10.8 or higher for TinyMCE 5.x.
- Upgrade to TinyMCE 6.7.1 or higher for TinyMCE 6.x.
Acknowledgements
Tiny Technologies would like to thank Masato Kinugawa of Cure53 for discovering this vulnerability.
References
For more information
If you have any questions or comments about this advisory:
- Email us at infosec@tiny.cloud
- Open an issue in the TinyMCE repo
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Paquete de Composer | tinymce/tinymce | >= 6.0.0, < 6.7.1, < 5.10.8 | 6.7.1, 5.10.8 |
| Paquete de npm | tinymce | >= 6.0.0, < 6.7.1, < 5.10.8 | 6.7.1, 5.10.8 |
| .NET (NuGet) | TinyMCE | >= 6.0.0, < 6.7.1, < 5.10.8 | 6.7.1, 5.10.8 |
Referencias
- https://github.com/tinymce/tinymce/security/advisories/GHSA-v65r-p3vv-jjfv
- https://nvd.nist.gov/vuln/detail/CVE-2023-45818
- https://github.com/tinymce/tinymce
- https://researchgate.net/publication/266654651_mXSS_attacks_Attacking_well-secured_web-applications_by_using_innerHTML_mutations
- https://tiny.cloud/docs/release-notes/release-notes5108/#securityfixes
- https://tiny.cloud/docs/tinymce/6/6.7.1-release-notes/#security-fixes
- https://www.tiny.cloud/docs/api/tinymce.html/tinymce.html.saxparser
- Vector CVSS
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N- Debilidad (CWE)
CWE-79- Plataforma
- Composer, npm, .NET (NuGet)
- Paquete
tinymce/tinymce, tinymce, TinyMCE- Publicada
- 19.10.2023
- Actualizado
- 11.10.2026 11:23
Fuentes y licencias
OSV / GitHub Advisory Database - GHSA-v65r-p3vv-jjfv - CC BY 4.0
Historial de vulnerabilidades: tinymce/tinymce
Todas las vulnerabilidades publicadas de este paquete (Paquete de Composer), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.
- Entradas en total
- 15
- Primera → última
- 01.2021 06.2026
- Sin corrección
- 0
- Explotada en ataques
- 0
Distribución por gravedad
- Alta 4
- Media 11
Divulgaciones por año
- 2021: 3
- 2022: 1
- 2023: 3
- 2024: 4
- 2025: 0
- 2026: 4
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TinyMCE mXSS vulnerability in undo/redo, getContent API, resetContent API, and Autosave plugin esta entrada
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