#VU53654 Cross-site scripting in Plone - CVE-2021-33513

Vulnerability identifier: #VU53654

Vulnerability risk: Low

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:Clear]

CVE-ID: CVE-2021-33513

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Plone
Web applications / CMS

Vendor: Plone

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 in the inline_diff methods in Products.CMFDiffTool. A remote authenticated attacker can trick the victim to follow a specially crafted link 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 update from vendor's website.

Vulnerable software versions

Plone: 5.0 rc1 - 5.2.4

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External links
https://plone.org/security/hotfix/20210518/xss-vulnerability-in-cmfdifftool
https://www.openwall.com/lists/oss-security/2021/05/22/1

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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.