Vulnerability identifier: #VU50054

Vulnerability risk: Low

CVSSv3.1: 4.1 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-26272

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
CKEditor
Web applications / JS libraries

Vendor: CKSource

Description

The vulnerability allows a remote attacker to perform a regular expression denial of service (ReDoS) attack.

The vulnerability exists due to insufficient validation of user-supplied input. A remote attacker can trick the victim to paste a specially crafted URL-like text into the editor, and then press Enter or Space (in the Autolink plugin) and perform a regular expression denial of service (ReDoS) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

CKEditor: 4.0.0 - 4.15.1

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External links
http://github.com/ckeditor/ckeditor4/blob/major/CHANGES.md#ckeditor-416

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.