CVE-2021-21391 describes a Regular Expression Denial of Service (ReDoS) vulnerability impacting multiple CKEditor 5 npm packages, including ckeditor5-engine, ckeditor5-font, and others, up to version 26.0.0. This flaw allows attackers to exploit specific regular expressions, causing a significant performance degradation and browser tab freezes for affected users. With a CVSS score of 6.5 (Medium), the vulnerability has a network attack vector and low attack complexity, requiring user interaction (UI:R) but leading to high availability impact (A:H) without affecting confidentiality or integrity. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
< 27.0.0CPE matchmatch criteria | cpe:2.3:a:ckeditor:ckeditor5-engine:*:*:*:*:*:node.js:*:* | ||
< 27.0.0CPE matchmatch criteria | cpe:2.3:a:ckeditor:ckeditor5-font:*:*:*:*:*:node.js:*:* | ||
< 27.0.0CPE matchmatch criteria | cpe:2.3:a:ckeditor:ckeditor5-image:*:*:*:*:*:node.js:*:* | ||
< 27.0.0CPE matchmatch criteria | cpe:2.3:a:ckeditor:ckeditor5-list:*:*:*:*:*:node.js:*:* | ||
< 27.0.0CPE matchmatch criteria | cpe:2.3:a:ckeditor:ckeditor5-markdown-gfm:*:*:*:*:*:node.js:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
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The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.