CVE-2021-21391: ckeditor ckeditor5 Uncontrolled Resource Consumption

Vulnerability summary

CVE-2021-21391 is a medium (CVSS 6.5) Uncontrolled Resource Consumption vulnerability in ckeditor ckeditor5. EPSS estimates a 1.67% chance of exploitation in the next 30 days, higher than 76.4% of scored vulnerabilities.

Timeline

1. 29-04-2021
   PublishedVulnerability first disclosed.
2. 03-08-2024
   Last modifiedVulnerability information updated.

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.

• CWE-400Uncontrolled Resource ConsumptionThe product does not properly control the allocation and maintenance of a limited resource.