CVE-2021-21391

Regular expression Denial of Service in multiple packages

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.

Category

6.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 1.35% Top 25%
Third-Party Advisory github.com
Affected: ckeditor ckeditor5
Published at:
Updated at:

References

Link Tags
https://www.npmjs.com/package/%40ckeditor/ckeditor5-markdown-gfm
https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-3rh3-wfr4-76mj third party advisory
https://www.npmjs.com/package/%40ckeditor/ckeditor5-engine
https://www.npmjs.com/package/%40ckeditor/ckeditor5-font
https://www.npmjs.com/package/%40ckeditor/ckeditor5-image
https://www.npmjs.com/package/%40ckeditor/ckeditor5-list
https://www.npmjs.com/package/%40ckeditor/ckeditor5-media-embed
https://www.npmjs.com/package/%40ckeditor/ckeditor5-paste-from-office
https://www.npmjs.com/package/%40ckeditor/ckeditor5-widget

Frequently Asked Questions

What is the severity of CVE-2021-21391?
CVE-2021-21391 has been scored as a medium severity vulnerability.
How to fix CVE-2021-21391?
To fix CVE-2021-21391, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-21391 being actively exploited in the wild?
It is possible that CVE-2021-21391 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~1% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-21391?
CVE-2021-21391 affects ckeditor ckeditor5.
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