CVE & CISA-KEV Catalog

CVE-2021-21391

MEDIUMEPSS 74th pctl
6.5
CVSS v3
NVD

Description

CKEditor 5 provides a WYSIWYG editing solution. This CVE affects the following npm packages: ckeditor5-engine, ckeditor5-font, ckeditor5-image, ckeditor5-list, ckeditor5-markdown-gfm, ckeditor5-media-embed, ckeditor5-paste-from-office, and ckeditor5-widget. Following an internal audit, a regular expression denial of service (ReDoS) vulnerability has been discovered in multiple CKEditor 5 packages. The vulnerability allowed to abuse particular regular expressions, which could cause a significant performance drop resulting in a browser tab freeze. It affects all users using the CKEditor 5 packages listed above at version <= 26.0.0. The problem has been recognized and patched. The fix will be available in version 27.0.0.

CWE-400Resource Exhaustion

How to fix

Remediation Available
ckeditor5-engineNVD
Affected:< 27.0.0Fixed in:27.0.0CVE-2021-21391derived from NVD
ckeditor5-fontNVD
Affected:< 27.0.0Fixed in:27.0.0CVE-2021-21391derived from NVD
ckeditor5-imageNVD
Affected:< 27.0.0Fixed in:27.0.0CVE-2021-21391derived from NVD
ckeditor5-listNVD
Affected:< 27.0.0Fixed in:27.0.0CVE-2021-21391derived from NVD
ckeditor5-markdown-gfmNVD
Affected:< 27.0.0Fixed in:27.0.0CVE-2021-21391derived from NVD
ckeditor5-media-embedNVD
Affected:< 27.0.0Fixed in:27.0.0CVE-2021-21391derived from NVD
ckeditor5-paste-from-officeNVD
Affected:< 27.0.0Fixed in:27.0.0CVE-2021-21391derived from NVD
ckeditor5-widgetNVD
Affected:< 27.0.0Fixed in:27.0.0CVE-2021-21391derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityNone
AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Exploit Intelligence

1.67%probability of exploitation in 30 days
74thpercentile

Elevated risk: more likely to be exploited than 74% of all known CVEs.

References

Third-Party Advisory1

Related Vulnerabilities

Other CWE-400 (Resource Exhaustion) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2023-44487High7.5100%KEVFix
CVE-2021-44228Critical10.0100%KEV + RansomFix
CVE-2011-3192High7.899%-Fix
CVE-2019-11478Medium5.395%-Fix
CVE-2024-25617Medium5.389%-Fix
CVE-2018-1000115High7.589%-Fix
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CVE-2021-21391 severity badge

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.