cve.bz

CVE-2021-21254

6.5 mediumEPSS 1.8%

Medium (6.5) in ckeditor ckeditor5. EPSS 1.8% chance of exploitation in the next 30 days. Fixed in @ckeditor/ckeditor5-markdown-gfm 25.0.0.

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.

Severity

CVSS 3.1

6.5 medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS
1.8% chance of exploitation in the next 30 days; higher than 78% of CVEs (scores of 2026-10-31)
CWE
CWE-400
Published
Modified
Record from
the NVD, synced

Affected

Packages (OSV)

AdvisoryEcosystemPackageAffectedFixed in
GHSA-hgmg-hhc8-g5wrnpm@ckeditor/ckeditor5-markdown-gfm<25.0.025.0.0

References

Check your stackJSON