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CVE-2021-21254

Regular expression Denial of Service in Markdown plugin

Published: Jan 29, 2021Updated: Nov 21, 2024 Sources: CVE List NVD GHSACWE-400
NVD MITRE
6.5CVSSMEDIUM
EPSS Score
1.8%
Top 24.5%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-400

Affected Products

ckeditor5ckeditor
On-prem
Web & CMS Plugins / cms-core
@ckeditor/ckeditor5-markdown-gfmnpmOSS Libraries
ckeditoross-projectWeb & CMS Pluginsaka ckeditor, ckeditor4, ckeditor5
npmpackage-ecosystemOSS Libraries

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-hgmg-hhc8-g5wr
github.com
https://github.com/ckeditor/ckeditor5/releases/tag/v25.0.0
github.com
https://www.npmjs.com/package/%40ckeditor/ckeditor5-markdown-gfm
npmjs.com
and 3 more references View all →

Timeline

Published
Jan 29, 2021
Last Updated
Nov 21, 2024

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