#VU58219 Cross-site scripting in CKEditor - CVE-2021-41165

Vulnerability identifier: #VU58219

Vulnerability risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-41165

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
CKEditor
Web applications / JS libraries

Vendor: CKSource

Description

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data when processing HTML comments. A remote attacker can inject and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

CKEditor: 4.0 basic - 4.16.2

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External links
https://github.com/ckeditor/ckeditor4/blob/major/CHANGES.md#ckeditor-417
https://github.com/ckeditor/ckeditor4/security/advisories/GHSA-7h26-63m7-qhf2

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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