GHSA-rgg8-g5x8-wr9v
HIGHCross-site scripting (XSS) in the clipboard package
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
ckeditor5npm@ckeditor/ckeditor5-clipboardnpmDescription
Impact
During a recent internal audit, we identified a Cross-Site Scripting (XSS) vulnerability in the CKEditor 5 clipboard package. This vulnerability could be triggered by a specific user action, leading to unauthorized JavaScript code execution, if the attacker managed to insert a malicious content into the editor, which might happen with a very specific editor configuration.
This vulnerability affects only installations where the editor configuration meets the following criteria:
- The Block Toolbar plugin is enabled.
- One of the following plugins is also enabled:
- General HTML Support with a configuration that permits unsafe markup.
- HTML Embed.
Patches
The problem has been recognized and patched. The fix will be available in version 43.1.1 (and above), and explicitly in version 41.3.2.
Workarounds
It's highly recommended to update to the version 43.1.1 or higher. However, if the update is not an option, we recommend disabling the block toolbar plugin.
For more information
Email us at [email protected] if you have any questions or comments about this advisory.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | ckeditor5 | ≥ 40.0.0&&< 43.1.1 | 43.1.1 |
| 📦npm | @ckeditor/ckeditor5-clipboard | ≥ 40.0.0&&< 43.1.1 | 43.1.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ckeditor5. 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 ckeditor5 to 43.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-rgg8-g5x8-wr9v 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-rgg8-g5x8-wr9v 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-rgg8-g5x8-wr9v. 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-rgg8-g5x8-wr9v in your dependencies?
O3 detects GHSA-rgg8-g5x8-wr9v across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.