CVE-2021-21391
Last modified
CVE-2021-21391 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. CKEditor 5 provides a WYSIWYG editing solution. This CVE affects the following npm packages: ckeditor5-engine, ckeditor5-font, ckeditor5-image, ckeditor5-list, ckeditor5-markdown-gfm, ckeditor5-media-embed, ckeditor5-paste-from-office, and ckeditor5-widget. EPSS estimates a 1.67% chance of exploitation in the next 30 days.
Description
CKEditor 5 provides a WYSIWYG editing solution. This CVE affects the following npm packages: ckeditor5-engine, ckeditor5-font, ckeditor5-image, ckeditor5-list, ckeditor5-markdown-gfm, ckeditor5-media-embed, ckeditor5-paste-from-office, and ckeditor5-widget. Following an internal audit, 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. The problem has been recognized and patched. The fix will be available in version 27.0.0.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Ckeditor | Ckeditor5-Engine | < 27.0.0 |
| Ckeditor | Ckeditor5-Font | < 27.0.0 |
| Ckeditor | Ckeditor5-Image | < 27.0.0 |
| Ckeditor | Ckeditor5-List | < 27.0.0 |
| Ckeditor | Ckeditor5-Markdown-Gfm | < 27.0.0 |
| Ckeditor | Ckeditor5-Media-Embed | < 27.0.0 |
| Ckeditor | Ckeditor5-Paste-From-Office | < 27.0.0 |
| Ckeditor | Ckeditor5-Widget | < 27.0.0 |
References
- https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-3rh3-wfr4-76mjThird Party Advisory
- https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-3rh3-wfr4-76mjThird Party Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
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How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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