CVE-2021-21254
MEDIUM6.5EPSS 0.37%CKEditor 5 Markdown plugin Regular expression Denial of Service
Description
### Impact A regular expression denial of service (ReDoS) vulnerability has been discovered in the CKEditor 5 Markdown plugin code. The vulnerability allowed to abuse a link recognition regular expression, which could cause a significant performance drop resulting in a browser tab freeze. It affects all users using the CKEditor 5 Markdown plugin at version <= 24.0.0. ### Patches The problem has been recognized and patched. The fix will be available in version 25.0.0. ### Workarounds The user can work around the issue by: - Upgrading CKEditor 5 to version 25.0.0. - Disabling the Markdown plugin. ### More information If you have any questions or comments about this advisory: * Email us at [[email protected]](mailto:[email protected]) ### Acknowledgements The CKEditor 5 team would like to thank Erik Krogh Kristensen from the GitHub team for recognizing this vulnerability and Alvaro Muñoz from GitHub for reporting it.
Affected packages (1)
- npm/@ckeditor/ckeditor5-markdown-gfmfrom 0, < 25.0.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
References (5)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2021-21254
- PATCHhttps://github.com/ckeditor/ckeditor5
- WEBhttps://github.com/ckeditor/ckeditor5/releases/tag/v25.0.0
- WEBhttps://github.com/ckeditor/ckeditor5/security/advisories/GHSA-hgmg-hhc8-g5wr
- WEBhttps://www.npmjs.com/package/@ckeditor/ckeditor5-markdown-gfm