GHSA-c78w-2gw7-gjv3
GHSA-c78w-2gw7-gjv3 is a Cross-site Scripting (XSS) vulnerability in tinymce. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-c78w-2gw7-gjv3 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
XSS in TinyMCE
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
tinymcenpmDescription
Impact
A cross-site scripting (XSS) vulnerability was discovered in: the core parser and media plugin. The vulnerability allowed arbitrary JavaScript execution when inserting a specially crafted piece of content into the editor via the clipboard or APIs. This impacts all users who are using TinyMCE 4.9.9 or lower and TinyMCE 5.2.1 or lower.
Patches
This vulnerability has been patched in TinyMCE 4.9.10 and 5.2.2 by improved HTML parsing and sanitization logic.
Workarounds
The workarounds available are:
- disable the media plugin and manually sanitize CDATA content (see below) or
- upgrade to either TinyMCE 4.9.10 or TinyMCE 5.2.2
Example: Manually strip CDATA elements
setup: function(editor) {
editor.on('PreInit', function() {
editor.parser.addNodeFilter('#cdata', function(nodes) {
for (var i = 0; i < nodes.length; i++) {
nodes[i].remove();
}
});
});
}
Acknowledgements
Tiny Technologies would like to thank Michał Bentkowski and intivesec for discovering these vulnerabilities.
References
https://www.tiny.cloud/docs/release-notes/release-notes522/#securityfixes
For more information
If you have any questions or comments about this advisory:
- Open an issue in the TinyMCE repo
- Email us at [email protected]
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | tinymce | all versions | 4.9.10 |
| 📦npm | tinymce | ≥ 5.0.0&&< 5.2.2 | 5.2.2 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tinymce. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update tinymce to 4.9.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-c78w-2gw7-gjv3 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-c78w-2gw7-gjv3 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-c78w-2gw7-gjv3. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-c78w-2gw7-gjv3 in your dependencies?
O3 detects GHSA-c78w-2gw7-gjv3 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.