CVE-2021-26271

It was possible to execute a ReDoS-type attack inside CKEditor 4 before 4.16 by persuading a victim to paste crafted text into the Styles input of specific dialogs (in the Advanced Tab for Dialogs plugin).

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CVSS v3.1

6.5 MEDIUM

EPSS

1.97%

probability of exploitation in 30 days

CISA KEV

Not listed

no confirmed exploitation reported

News coverage

sources referencing this CVE

EPSS Trend

Aug 16, 2026 → Aug 30, 2026

● 0.01pp

1.96% → 1.97% over 3 tracked changes

CVSS v3.1 Detail

Attack VectorNETWORK

Attack ComplexityLOW

Privileges RequiredNONE

User InteractionREQUIRED

ScopeUNCHANGED

ConfidentialityNONE

IntegrityNONE

AvailabilityHIGH

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

Connections

9 relationships

CWE-829

source

Timeline

disclosure → media coverage

Jan 26, 2021

Disclosure — published as a CVE record. · last revised by NVD Aug 25, 2026