CVE-2021-21391
CKEditor 5 Regular Expression Denial of Service 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.
INFO
Published Date :
April 29, 2021, 1:15 a.m.
Last Modified :
Nov. 7, 2023, 3:30 a.m.
Source :
[email protected]
Remotely Exploitable :
Yes !
Impact Score :
3.6
Exploitability Score :
2.8
Public PoC/Exploit Available at Github
CVE-2021-21391 has a 1 public PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
Affected Products
The following products are affected by CVE-2021-21391
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-21391.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
List of RegEx DoS (ReDoS) CVEs and resources
security awesome redos regex dos regex-dos pentesting awesome-list regex-security
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-21391 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-21391 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
CVE Modified by [email protected]
Nov. 07, 2023
Action Type Old Value New Value Added Reference GitHub, Inc. https://www.npmjs.com/package/%40ckeditor/ckeditor5-markdown-gfm [No types assigned] Added Reference GitHub, Inc. https://www.npmjs.com/package/%40ckeditor/ckeditor5-engine [No types assigned] Added Reference GitHub, Inc. https://www.npmjs.com/package/%40ckeditor/ckeditor5-font [No types assigned] Added Reference GitHub, Inc. https://www.npmjs.com/package/%40ckeditor/ckeditor5-image [No types assigned] Added Reference GitHub, Inc. https://www.npmjs.com/package/%40ckeditor/ckeditor5-list [No types assigned] Added Reference GitHub, Inc. https://www.npmjs.com/package/%40ckeditor/ckeditor5-media-embed [No types assigned] Added Reference GitHub, Inc. https://www.npmjs.com/package/%40ckeditor/ckeditor5-paste-from-office [No types assigned] Added Reference GitHub, Inc. https://www.npmjs.com/package/%40ckeditor/ckeditor5-widget [No types assigned] Removed Reference GitHub, Inc. https://www.npmjs.com/package/@ckeditor/ckeditor5-markdown-gfm Removed Reference GitHub, Inc. https://www.npmjs.com/package/@ckeditor/ckeditor5-engine Removed Reference GitHub, Inc. https://www.npmjs.com/package/@ckeditor/ckeditor5-image Removed Reference GitHub, Inc. https://www.npmjs.com/package/@ckeditor/ckeditor5-media-embed Removed Reference GitHub, Inc. https://www.npmjs.com/package/@ckeditor/ckeditor5-list Removed Reference GitHub, Inc. https://www.npmjs.com/package/@ckeditor/ckeditor5-font Removed Reference GitHub, Inc. https://www.npmjs.com/package/@ckeditor/ckeditor5-paste-from-office Removed Reference GitHub, Inc. https://www.npmjs.com/package/@ckeditor/ckeditor5-widget -
Initial Analysis by [email protected]
May. 10, 2021
Action Type Old Value New Value Added CVSS V2 Metadata Victim must voluntarily interact with attack mechanism Added CVSS V2 NIST (AV:N/AC:M/Au:N/C:N/I:N/A:P) Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Changed Reference Type https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-3rh3-wfr4-76mj No Types Assigned https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-3rh3-wfr4-76mj Third Party Advisory Changed Reference Type https://www.npmjs.com/package/@ckeditor/ckeditor5-engine No Types Assigned https://www.npmjs.com/package/@ckeditor/ckeditor5-engine Product, Third Party Advisory Changed Reference Type https://www.npmjs.com/package/@ckeditor/ckeditor5-font No Types Assigned https://www.npmjs.com/package/@ckeditor/ckeditor5-font Product, Third Party Advisory Changed Reference Type https://www.npmjs.com/package/@ckeditor/ckeditor5-image No Types Assigned https://www.npmjs.com/package/@ckeditor/ckeditor5-image Product, Third Party Advisory Changed Reference Type https://www.npmjs.com/package/@ckeditor/ckeditor5-list No Types Assigned https://www.npmjs.com/package/@ckeditor/ckeditor5-list Product, Third Party Advisory Changed Reference Type https://www.npmjs.com/package/@ckeditor/ckeditor5-markdown-gfm No Types Assigned https://www.npmjs.com/package/@ckeditor/ckeditor5-markdown-gfm Product, Third Party Advisory Changed Reference Type https://www.npmjs.com/package/@ckeditor/ckeditor5-media-embed No Types Assigned https://www.npmjs.com/package/@ckeditor/ckeditor5-media-embed Product, Third Party Advisory Changed Reference Type https://www.npmjs.com/package/@ckeditor/ckeditor5-paste-from-office No Types Assigned https://www.npmjs.com/package/@ckeditor/ckeditor5-paste-from-office Product, Third Party Advisory Changed Reference Type https://www.npmjs.com/package/@ckeditor/ckeditor5-widget No Types Assigned https://www.npmjs.com/package/@ckeditor/ckeditor5-widget Product, Third Party Advisory Added CPE Configuration OR *cpe:2.3:a:ckeditor:ckeditor5-engine:*:*:*:*:*:node.js:*:* versions up to (excluding) 27.0.0 *cpe:2.3:a:ckeditor:ckeditor5-font:*:*:*:*:*:node.js:*:* versions up to (excluding) 27.0.0 *cpe:2.3:a:ckeditor:ckeditor5-image:*:*:*:*:*:node.js:*:* versions up to (excluding) 27.0.0 *cpe:2.3:a:ckeditor:ckeditor5-list:*:*:*:*:*:node.js:*:* versions up to (excluding) 27.0.0 *cpe:2.3:a:ckeditor:ckeditor5-markdown-gfm:*:*:*:*:*:node.js:*:* versions up to (excluding) 27.0.0 *cpe:2.3:a:ckeditor:ckeditor5-media-embed:*:*:*:*:*:node.js:*:* versions up to (excluding) 27.0.0 *cpe:2.3:a:ckeditor:ckeditor5-paste-from-office:*:*:*:*:*:node.js:*:* versions up to (excluding) 27.0.0 *cpe:2.3:a:ckeditor:ckeditor5-widget:*:*:*:*:*:node.js:*:* versions up to (excluding) 27.0.0
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-21391 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-21391
weaknesses.
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
0.48 }} 0.06%
score
0.73307
percentile