6.5

CVE-2021-21254: ckeditor ckeditor5 Uncontrolled Resource Consumption

CVSS: 6.5v3.1MediumModified
AliasesGHSA-hgmg-hhc8-g5wr
Published 29-01-2021Last modified 03-08-2024
Open JSON

Vulnerability summary

CVE-2021-21254 is a medium (CVSS 6.5) Uncontrolled Resource Consumption vulnerability in ckeditor ckeditor5. EPSS estimates a 1.79% chance of exploitation in the next 30 days, higher than 78% of scored vulnerabilities.

Overall risk
26/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
1.79%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 29-01-2021
    PublishedVulnerability first disclosed.
  2. 03-08-2024
    Last modifiedVulnerability information updated.

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 metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

1.79%

Chance of exploitation in the next 30 days

Percentile

78%

Versus all other CVEs

30-day change

0.00 pp

From 1.79% on 19-09-2026

19-09-202619-10-2026
EPSS score
1.79%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

@ckeditor1 product
  • ckeditor5-markdown-gfm< 25.0.0
Ckeditor1 product

2 vendors · 2 products

References

6 links