GHSA-3rh3-wfr4-76mj
MEDIUMGHSA-3rh3-wfr4-76mj is a medium-severity (CVSS 6.5) Uncontrolled Resource Consumption vulnerability in @ckeditor/ckeditor5-engine. O3 Security confirms whether GHSA-3rh3-wfr4-76mj is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Regular expression Denial of Service in multiple packages
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
@ckeditor/ckeditor5-enginenpm@ckeditor/ckeditor5-fontnpm@ckeditor/ckeditor5-imagenpmDescription
Impact
A regular expression denial of service (ReDoS) vulnerability has been discovered in multiple CKEditor 5 packages. The vulnerability allowed to abuse particular regular expressions, which could cause a significant performance drop resulting in a browser tab freeze. It affects all users using the CKEditor 5 packages listed above at version <= 26.0.0.
Patches
The problem has been recognized and patched. The fix will be available in version 27.0.0.
For more information
Email us at [email protected] if you have any questions or comments about this advisory.
Acknowledgements
The CKEditor 5 team would like to thank Yeting Li for recognizing and reporting these vulnerabilities.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @ckeditor/ckeditor5-engine | all versions | 27.0.0 |
| 📦npm | @ckeditor/ckeditor5-font | all versions | 27.0.0 |
| 📦npm | @ckeditor/ckeditor5-image | all versions | 27.0.0 |
| 📦npm | @ckeditor/ckeditor5-list | all versions | 27.0.0 |
| 📦npm | @ckeditor/ckeditor5-markdown-gfm | all versions | 27.0.0 |
| 📦npm | @ckeditor/ckeditor5-media-embed | all versions | 27.0.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @ckeditor/ckeditor5-engine. 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 @ckeditor/ckeditor5-engine to 27.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3rh3-wfr4-76mj 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-3rh3-wfr4-76mj 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-3rh3-wfr4-76mj. 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-3rh3-wfr4-76mj in your dependencies?
O3 detects GHSA-3rh3-wfr4-76mj across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.