Cross-site scripting vulnerability in TinyMCE plugins
Impact
A cross-site scripting (XSS) vulnerability was discovered in the URL processing logic of the image and link plugins. The vulnerability allowed arbitrary JavaScript execution when updating an image or link using a specially crafted URL. This issue only impacted users while editing and the dangerous URLs were stripped in any content extracted from the editor. This impacts all users who are using TinyMCE 5.9.2 or lower.
Patches
This vulnerability has been patched in TinyMCE 5.10.0 by improved sanitization logic when updating URLs in the relevant plugins.
Workarounds
To work around this vulnerability, either:
- Upgrade to TinyMCE 5.10.0 or higher
- Disable the
imageandlinkplugins
Acknowledgements
Tiny Technologies would like to thank Yakir6 for discovering this vulnerability.
References
https://www.tiny.cloud/docs/release-notes/release-notes510/#securityfixes
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
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | tinymce/tinymce | < 5.10.0 | 5.10.0 |
| npm package | tinymce | < 5.10.0 | 5.10.0 |
| .NET (NuGet) | TinyMCE | < 5.10.0 | 5.10.0 |
| Python (PyPI) | django-tinymce | < 3.4.0 | 3.4.0 |
References
- https://github.com/tinymce/tinymce/security/advisories/GHSA-r8hm-w5f7-wj39
- https://github.com/jazzband/django-tinymce/issues/366
- https://github.com/jazzband/django-tinymce/releases/tag/3.4.0
- https://github.com/tinymce/tinymce
- https://pypi.org/project/django-tinymce/3.4.0
- https://pypi.org/project/django-tinymce
- https://github.com/advisories/GHSA-r8hm-w5f7-wj39
- https://nvd.nist.gov/vuln/detail/CVE-2024-21910
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N- Weakness (CWE)
CWE-64, CWE-79- Platform
- Composer, npm, .NET (NuGet), Python (PyPI)
- Package
tinymce/tinymce, tinymce, TinyMCE- Disclosed
- 02.11.2021
- Updated
- 11.10.2026 13:17
Sources and licenses
OSV / GitHub Advisory Database - GHSA-r8hm-w5f7-wj39 - CC BY 4.0
OSV / GitHub Advisory Database - PYSEC-2026-632 - PyPA Advisory Database; CC BY 4.0
Vulnerability history: TinyMCE
All published vulnerabilities of this package (.NET (NuGet)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 15
- First → latest
- 01.2021 06.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 4
- Medium 11
Disclosures per year
- 2021: 3
- 2022: 1
- 2023: 3
- 2024: 4
- 2025: 0
- 2026: 4
-
Cross-site scripting vulnerability in TinyMCE plugins this entry
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