Vulnerability Report

CVE-2021-21391

Title: CKEditor 5 Regex Denial of Service (ReDoS)

DoS

Proof Of Concept

No public PoC currently indexed for CVE-2021-21391.

CWE Category CWE-400
Published Date Apr 29, 2021
Modified Date Nov 21, 2024
Exploit Status Not Found
Score 6.5 CVSS v3.1
Exploit Probability (EPSS)
1.67%

Vulnerability Summary

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-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.

Impacted Vendors

C
ckeditor 8

Reference Links

https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-3rh3-wfr4-76mj 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-markdown-gfm 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 https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-3rh3-wfr4-76mj 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-markdown-gfm 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
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
6.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
REQUIRED
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
6.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
REQUIRED
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS v2.0
Source Entity [email protected]
Severity MEDIUM
4.3
Access Vector
N/A
Authentication
N/A
RAW VECTOR AV:N/AC:M/Au:N/C:N/I:N/A:P

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2021-21391 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data or affected products updated.

PUBLISHED

Vulnerability first announced in NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction REQUIRED
CVSS Vector String CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected Stack

No specific products linked.