Resource exhaustion in Ckeditor Ckeditor5
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. The fix will be available in version 25.0.0.
Vulnerability class: DoS (Denial of Service)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.018 (77.5th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 78th percentile — 77.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.018 · newest: 0.018 · change: 0.000
Affected products
- Ckeditor Ckeditor5 — versions < 25.0.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/ckeditor/ckeditor5/security/advisories/GHSA-hgmg-hhc8-g5wr (Third Party Advisory)
- github.com/ckeditor/ckeditor5/releases/tag/v25.0.0 (Third Party Advisory, Release Notes)
- www.npmjs.com/package/@ckeditor/ckeditor5-markdown-gfm
Frequently asked questions
- What is CVE-2021-21254?
- CVE-2021-21254 is a medium-severity vulnerability in Ckeditor Ckeditor5, classified under Uncontrolled Resource Consumption. CVSS score: 6.5/10. Published 2021-01-29.
- How severe is CVE-2021-21254?
- Medium severity. CVSS v3 base score is 6.5 out of 10.
- Is CVE-2021-21254 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.