CVE-2021-21391
moderate-risk
Published 2021-04-29
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.
Do I need to act?
~
8.3% chance of exploitation in next 30 days
EPSS score — moderate exploit probability
-
Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
6
CVSS 6.5/10
Medium
NETWORK
/ LOW complexity
Affected Products (8)
Ckeditor5-Engine
Ckeditor5-Font
Ckeditor5-Image
Ckeditor5-List
Ckeditor5-Markdown-Gfm
Ckeditor5-Media-Embed
Ckeditor5-Paste-From-Office
Ckeditor5-Widget
Affected Vendors
References (18)
Third Party Advisory
https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-3rh3-wfr4-76mj
Third Party Advisory
https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-3rh3-wfr4-76mj
48
/ 100
moderate-risk
Severity
24/34 · High
Exploitability
10/34 · Low
Exposure
14/34 · Moderate