Vulnerability Report

CVE-2021-26272

Title: CKEditor 4 ReDoS via Autolink plugin

DoS

Proof Of Concept

No public PoC currently indexed for CVE-2021-26272.

CWE Category CWE-829
Published Date Jan 26, 2021
Modified Date Aug 25, 2026
Exploit Status Not Found
Score 6.5 CVSS v3.1
Exploit Probability (EPSS)
2.22%

Vulnerability Summary

CVE-2021-26272: It was possible to execute a ReDoS-type attack inside CKEditor 4 before 4.16 by persuading a victim to paste crafted URL-like text into the editor, and then press Enter or Space (in the Autolink plugin).

Impacted Vendors

C
cksource 1
O
oracle 10
C
ckeditor 1

Reference Links

https://ckeditor.com/blog/CKEditor-4.16-with-improved-image-pasting-High-Contrast-support-and-a-new-color-API/#security-comes-first https://github.com/ckeditor/ckeditor4/blob/major/CHANGES.md#ckeditor-416 https://www.oracle.com//security-alerts/cpujul2021.html https://www.oracle.com/security-alerts/cpujan2022.html https://www.oracle.com/security-alerts/cpuoct2021.html https://ckeditor.com/blog/CKEditor-4.16-with-improved-image-pasting-High-Contrast-support-and-a-new-color-API/#security-comes-first https://github.com/ckeditor/ckeditor4/blob/major/CHANGES.md#ckeditor-416 https://www.oracle.com//security-alerts/cpujul2021.html https://www.oracle.com/security-alerts/cpujan2022.html https://www.oracle.com/security-alerts/cpuoct2021.html
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
6.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
REQUIRED
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS v2.0
Source Entity [email protected]
Severity MEDIUM
4.3
Access Vector
N/A
Authentication
N/A
RAW VECTOR AV:N/AC:M/Au:N/C:N/I:N/A:P

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2021-26272 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data or affected products updated.

PUBLISHED

Vulnerability first announced in NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction REQUIRED
CVSS Vector String CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected Stack

No specific products linked.