CVE-2021-21254

MEDIUM

CKEditor 5 Markdown Plugin < 25.0.0 - Denial of Service via Link Recognition Regex

Title source: llm
STIX 2.1

Description

CKEditor 5 is an open source rich text editor framework with a modular architecture. The CKEditor 5 Markdown plugin (@ckeditor/ckeditor5-markdown-gfm) before version 25.0.0 has a regex denial of service (ReDoS) vulnerability. The vulnerability allowed to abuse link recognition regular expression, which could cause a significant performance drop resulting in browser tab freeze. It affects all users using CKEditor 5 Markdown plugin at version <= 24.0.0. The problem has been recognized and patched. The fix will be available in version 25.0.0.

References (3)

Core 3
Core References
Release Notes, Third Party Advisory x_refsource_misc
https://github.com/ckeditor/ckeditor5/releases/tag/v25.0.0

Scores

CVSS v3 6.5
EPSS 0.0179
EPSS Percentile 75.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Details

CWE
CWE-400
Status published
Products (2)
ckeditor/ckeditor5 < 25.0.0
ckeditor/ckeditor5-markdown-gfm 0 - 25.0.0npm
Published Jan 29, 2021
Tracked Since Feb 18, 2026