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MEDIUM · 6.5

CVE-2021-21391

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-...

Vulnerability 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.

CVSS Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH

Affected Products

VendorProductVersions
CkeditorCkeditor5-Engine< 27.0.0
CkeditorCkeditor5-Font< 27.0.0
CkeditorCkeditor5-Image< 27.0.0
CkeditorCkeditor5-List< 27.0.0
CkeditorCkeditor5-Markdown-Gfm< 27.0.0
CkeditorCkeditor5-Media-Embed< 27.0.0
CkeditorCkeditor5-Paste-From-Office< 27.0.0
CkeditorCkeditor5-Widget< 27.0.0

Related Weaknesses (CWE)

CWE-400

References

FAQ

What is CVE-2021-21391?

CVE-2021-21391 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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-...

How severe is CVE-2021-21391?

CVE-2021-21391 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2021-21391?

Check the references section above for vendor advisories and patch information. Affected products include: Ckeditor Ckeditor5-Engine, Ckeditor Ckeditor5-Font, Ckeditor Ckeditor5-Image, Ckeditor Ckeditor5-List, Ckeditor Ckeditor5-Markdown-Gfm.