CVE-2021-21254 – Regular expression Denial of Service in Markdown plugin

https://notcve.org/view.php?id=CVE-2021-21254

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. • https://github.com/ckeditor/ckeditor5/releases/tag/v25.0.0 https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-hgmg-hhc8-g5wr https://www.npmjs.com/package/%40ckeditor/ckeditor5-markdown-gfm • CWE-400: Uncontrolled Resource Consumption •