CVE-2024-43407
MEDIUMCVE-2024-43407 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in ckeditor4. O3 Security confirms whether CVE-2024-43407 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Code Snippet GeSHi plugin has reflected cross-site scripting (XSS) vulnerability
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
ckeditor4npmDescription
CKEditor4 is an open source what-you-see-is-what-you-get HTML editor. A potential vulnerability has been discovered in CKEditor 4 Code Snippet GeSHi plugin. The vulnerability allowed a reflected XSS attack by exploiting a flaw in the GeSHi syntax highlighter library hosted by the victim. The GeSHi library was included as a vendor dependency in CKEditor 4 source files. In a specific scenario, an attacker could craft a malicious script that could be executed by sending a request to the GeSHi library hosted on a PHP web server. The GeSHi library is no longer actively maintained. Due to the lack of ongoing support and updates, potential security vulnerabilities have been identified with its continued use. To mitigate these risks and enhance the overall security of the CKEditor 4, we have decided to completely remove the GeSHi library as a dependency. This change aims to maintain a secure environment and reduce the risk of any security incidents related to outdated or unsupported software. The fix is be available in version 4.25.0-lts.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | ckeditor4 | all versions | 4.25.0 |
| 🐘Packagist | ckeditor/ckeditor | all versions | 4.25.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ckeditor4. 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 ckeditor4 to 4.25.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-43407 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 CVE-2024-43407 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 CVE-2024-43407. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2024-43407 in your dependencies?
O3 detects CVE-2024-43407 across npm, Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.